
import java.util.*;
import java.io.*;
public class Main {
    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        long n = fs.nextLong();
        List<Long> factors = new ArrayList<>();
        for(long i=1;i*i<=n;i++){
            if(n%i==0){
                factors.add(n/i);
            }
        }
        long val = factors.get(factors.size()-1);
        int digit = 0;
        while(val > 0){
            val/=10;
            digit++;
        }
        System.out.println(digit);
    }
    static class FastScanner {
            private final InputStream in = System.in;
            private final byte[] buffer = new byte[1024];
            private int ptr = 0;
            private int buflen = 0;
            private boolean hasNextByte() {
                if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                }
                return true;
            }
            private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
            private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
            public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
            public String next() {
                if (!hasNext()) throw new NoSuchElementException();
                StringBuilder sb = new StringBuilder();
                int b = readByte();
                while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                }
                return sb.toString();
            }
            public long nextLong() {
                if (!hasNext()) throw new NoSuchElementException();
                long n = 0;
                boolean minus = false;
                int b = readByte();
                if (b == '-') {
                    minus = true;
                    b = readByte();
                }
                if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                }
                while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                }
            }
            public int nextInt() {
                long nl = nextLong();
                if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
                return (int) nl;
            }
            public double nextDouble() { return Double.parseDouble(next());}
        }
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        long n = fs.nextLong();
        List<Long> factors = new ArrayList<>();
        for(long i=1;i*i<=n;i++){
            if(n%i==0){
                factors.add(n/i);
            }
        }
        long val = factors.get(factors.size()-1);
        int digit = 0;
        while(val > 0){
            val/=10;
            digit++;
        }
        System.out.println(digit);
    }
    static class FastScanner {
            private final InputStream in = System.in;
            private final byte[] buffer = new byte[1024];
            private int ptr = 0;
            private int buflen = 0;
            private boolean hasNextByte() {
                if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                }
                return true;
            }
            private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
            private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
            public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
            public String next() {
                if (!hasNext()) throw new NoSuchElementException();
                StringBuilder sb = new StringBuilder();
                int b = readByte();
                while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                }
                return sb.toString();
            }
            public long nextLong() {
                if (!hasNext()) throw new NoSuchElementException();
                long n = 0;
                boolean minus = false;
                int b = readByte();
                if (b == '-') {
                    minus = true;
                    b = readByte();
                }
                if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                }
                while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                }
            }
            public int nextInt() {
                long nl = nextLong();
                if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
                return (int) nl;
            }
            public double nextDouble() { return Double.parseDouble(next());}
        }
} Main public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        long n = fs.nextLong();
        List<Long> factors = new ArrayList<>();
        for(long i=1;i*i<=n;i++){
            if(n%i==0){
                factors.add(n/i);
            }
        }
        long val = factors.get(factors.size()-1);
        int digit = 0;
        while(val > 0){
            val/=10;
            digit++;
        }
        System.out.println(digit);
    } main {
        FastScanner fs = new FastScanner();
        long n = fs.nextLong();
        List<Long> factors = new ArrayList<>();
        for(long i=1;i*i<=n;i++){
            if(n%i==0){
                factors.add(n/i);
            }
        }
        long val = factors.get(factors.size()-1);
        int digit = 0;
        while(val > 0){
            val/=10;
            digit++;
        }
        System.out.println(digit);
    } FastScanner fs = new FastScanner(); fs new FastScanner() long n = fs.nextLong(); n fs.nextLong() fs.nextLong fs List<Long> factors = new ArrayList<>(); factors new ArrayList<>() for(long i=1;i*i<=n;i++){
            if(n%i==0){
                factors.add(n/i);
            }
        } long i=1; long i=1; i 1 i*i<=n i*i i i n i++ i++ i {
            if(n%i==0){
                factors.add(n/i);
            }
        } {
            if(n%i==0){
                factors.add(n/i);
            }
        } if(n%i==0){
                factors.add(n/i);
            } n%i==0 n%i n i 0 {
                factors.add(n/i);
            } factors.add(n/i) factors.add factors n/i n i long val = factors.get(factors.size()-1); val factors.get(factors.size()-1) factors.get factors factors.size()-1 factors.size() factors.size factors 1 int digit = 0; digit 0 while(val > 0){
            val/=10;
            digit++;
        } val > 0 val 0 {
            val/=10;
            digit++;
        } val/=10 val 10 digit++ digit System.out.println(digit) System.out.println System.out System System.out digit String[] args args static class FastScanner {
            private final InputStream in = System.in;
            private final byte[] buffer = new byte[1024];
            private int ptr = 0;
            private int buflen = 0;
            private boolean hasNextByte() {
                if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                }
                return true;
            }
            private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
            private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
            public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
            public String next() {
                if (!hasNext()) throw new NoSuchElementException();
                StringBuilder sb = new StringBuilder();
                int b = readByte();
                while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                }
                return sb.toString();
            }
            public long nextLong() {
                if (!hasNext()) throw new NoSuchElementException();
                long n = 0;
                boolean minus = false;
                int b = readByte();
                if (b == '-') {
                    minus = true;
                    b = readByte();
                }
                if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                }
                while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                }
            }
            public int nextInt() {
                long nl = nextLong();
                if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
                return (int) nl;
            }
            public double nextDouble() { return Double.parseDouble(next());}
        } FastScanner private final InputStream in = System.in; in System.in System System.in private final byte[] buffer = new byte[1024]; buffer new byte[1024] 1024 private int ptr = 0; ptr 0 private int buflen = 0; buflen 0 private boolean hasNextByte() {
                if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                }
                return true;
            } hasNextByte {
                if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                }
                return true;
            } if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                } ptr < buflen ptr buflen {
                    return true;
                } return true; true {
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                } ptr = 0 ptr 0 try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    } IOException e {
                        e.printStackTrace();
                    } e.printStackTrace() e.printStackTrace e {
                        buflen = in.read(buffer);
                    } buflen = in.read(buffer) buflen in.read(buffer) in.read in buffer if (buflen <= 0) {
                        return false;
                    } buflen <= 0 buflen 0 {
                        return false;
                    } return false; false return true; true private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} readByte { if (hasNextByte()) return buffer[ptr++]; else return -1;} if (hasNextByte()) return buffer[ptr++]; else return -1; hasNextByte() hasNextByte return buffer[ptr++]; buffer[ptr++] buffer ptr++ ptr return -1; -1 1 private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} isPrintableChar { return 33 <= c && c <= 126;} return 33 <= c && c <= 126; 33 <= c && c <= 126 33 <= c 33 c c <= 126 c 126 int c c public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();} hasNext { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();} while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; hasNextByte() && !isPrintableChar(buffer[ptr]) hasNextByte() hasNextByte !isPrintableChar(buffer[ptr]) isPrintableChar(buffer[ptr]) isPrintableChar buffer[ptr] buffer ptr ptr++ ptr return hasNextByte(); hasNextByte() hasNextByte public String next() {
                if (!hasNext()) throw new NoSuchElementException();
                StringBuilder sb = new StringBuilder();
                int b = readByte();
                while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                }
                return sb.toString();
            } next {
                if (!hasNext()) throw new NoSuchElementException();
                StringBuilder sb = new StringBuilder();
                int b = readByte();
                while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                }
                return sb.toString();
            } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() StringBuilder sb = new StringBuilder(); sb new StringBuilder() int b = readByte(); b readByte() readByte while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                } isPrintableChar(b) isPrintableChar b {
                    sb.appendCodePoint(b);
                    b = readByte();
                } sb.appendCodePoint(b) sb.appendCodePoint sb b b = readByte() b readByte() readByte return sb.toString(); sb.toString() sb.toString sb public long nextLong() {
                if (!hasNext()) throw new NoSuchElementException();
                long n = 0;
                boolean minus = false;
                int b = readByte();
                if (b == '-') {
                    minus = true;
                    b = readByte();
                }
                if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                }
                while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                }
            } nextLong {
                if (!hasNext()) throw new NoSuchElementException();
                long n = 0;
                boolean minus = false;
                int b = readByte();
                if (b == '-') {
                    minus = true;
                    b = readByte();
                }
                if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                }
                while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                }
            } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() long n = 0; n 0 boolean minus = false; minus false int b = readByte(); b readByte() readByte if (b == '-') {
                    minus = true;
                    b = readByte();
                } b == '-' b '-' {
                    minus = true;
                    b = readByte();
                } minus = true minus true b = readByte() b readByte() readByte if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                } b < '0' || '9' < b b < '0' b '0' '9' < b '9' b {
                    throw new NumberFormatException();
                } throw new NumberFormatException(); new NumberFormatException() while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                } true {
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                } if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    } '0' <= b && b <= '9' '0' <= b '0' b b <= '9' b '9' {
                        n *= 10;
                        n += b - '0';
                    } n *= 10 n 10 n += b - '0' n b - '0' b '0' if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    } b == -1 || !isPrintableChar(b) b == -1 b -1 1 !isPrintableChar(b) isPrintableChar(b) isPrintableChar b {
                        return minus ? -n : n;
                    } return minus ? -n : n; minus ? -n : n minus -n n n {
                        throw new NumberFormatException();
                    } throw new NumberFormatException(); new NumberFormatException() b = readByte() b readByte() readByte public int nextInt() {
                long nl = nextLong();
                if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
                return (int) nl;
            } nextInt {
                long nl = nextLong();
                if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
                return (int) nl;
            } long nl = nextLong(); nl nextLong() nextLong if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException(); nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE nl < Integer.MIN_VALUE nl Integer.MIN_VALUE Integer Integer.MIN_VALUE nl > Integer.MAX_VALUE nl Integer.MAX_VALUE Integer Integer.MAX_VALUE throw new NumberFormatException(); new NumberFormatException() return (int) nl; (int) nl public double nextDouble() { return Double.parseDouble(next());} nextDouble { return Double.parseDouble(next());} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next public class Main {
    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        long n = fs.nextLong();
        List<Long> factors = new ArrayList<>();
        for(long i=1;i*i<=n;i++){
            if(n%i==0){
                factors.add(n/i);
            }
        }
        long val = factors.get(factors.size()-1);
        int digit = 0;
        while(val > 0){
            val/=10;
            digit++;
        }
        System.out.println(digit);
    }
    static class FastScanner {
            private final InputStream in = System.in;
            private final byte[] buffer = new byte[1024];
            private int ptr = 0;
            private int buflen = 0;
            private boolean hasNextByte() {
                if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                }
                return true;
            }
            private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
            private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
            public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
            public String next() {
                if (!hasNext()) throw new NoSuchElementException();
                StringBuilder sb = new StringBuilder();
                int b = readByte();
                while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                }
                return sb.toString();
            }
            public long nextLong() {
                if (!hasNext()) throw new NoSuchElementException();
                long n = 0;
                boolean minus = false;
                int b = readByte();
                if (b == '-') {
                    minus = true;
                    b = readByte();
                }
                if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                }
                while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                }
            }
            public int nextInt() {
                long nl = nextLong();
                if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
                return (int) nl;
            }
            public double nextDouble() { return Double.parseDouble(next());}
        }
} public class Main {
    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        long n = fs.nextLong();
        List<Long> factors = new ArrayList<>();
        for(long i=1;i*i<=n;i++){
            if(n%i==0){
                factors.add(n/i);
            }
        }
        long val = factors.get(factors.size()-1);
        int digit = 0;
        while(val > 0){
            val/=10;
            digit++;
        }
        System.out.println(digit);
    }
    static class FastScanner {
            private final InputStream in = System.in;
            private final byte[] buffer = new byte[1024];
            private int ptr = 0;
            private int buflen = 0;
            private boolean hasNextByte() {
                if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                }
                return true;
            }
            private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
            private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
            public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
            public String next() {
                if (!hasNext()) throw new NoSuchElementException();
                StringBuilder sb = new StringBuilder();
                int b = readByte();
                while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                }
                return sb.toString();
            }
            public long nextLong() {
                if (!hasNext()) throw new NoSuchElementException();
                long n = 0;
                boolean minus = false;
                int b = readByte();
                if (b == '-') {
                    minus = true;
                    b = readByte();
                }
                if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                }
                while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                }
            }
            public int nextInt() {
                long nl = nextLong();
                if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
                return (int) nl;
            }
            public double nextDouble() { return Double.parseDouble(next());}
        }
} Main

import java.util.*;
import java.io.*;
public class Main {
    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        long n = fs.nextLong();
        List<Long> factors = new ArrayList<>();
        for(long i=1;i*i<=n;i++){
            if(n%i==0){
                factors.add(n/i);
            }
        }
        long val = factors.get(factors.size()-1);
        int digit = 0;
        while(val > 0){
            val/=10;
            digit++;
        }
        System.out.println(digit);
    }
    static class FastScanner {
            private final InputStream in = System.in;
            private final byte[] buffer = new byte[1024];
            private int ptr = 0;
            private int buflen = 0;
            private boolean hasNextByte() {
                if (ptr < buflen) {
                    return true;
                }else{
                    ptr = 0;
                    try {
                        buflen = in.read(buffer);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    if (buflen <= 0) {
                        return false;
                    }
                }
                return true;
            }
            private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
            private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
            public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
            public String next() {
                if (!hasNext()) throw new NoSuchElementException();
                StringBuilder sb = new StringBuilder();
                int b = readByte();
                while(isPrintableChar(b)) {
                    sb.appendCodePoint(b);
                    b = readByte();
                }
                return sb.toString();
            }
            public long nextLong() {
                if (!hasNext()) throw new NoSuchElementException();
                long n = 0;
                boolean minus = false;
                int b = readByte();
                if (b == '-') {
                    minus = true;
                    b = readByte();
                }
                if (b < '0' || '9' < b) {
                    throw new NumberFormatException();
                }
                while(true){
                    if ('0' <= b && b <= '9') {
                        n *= 10;
                        n += b - '0';
                    }else if(b == -1 || !isPrintableChar(b)){
                        return minus ? -n : n;
                    }else{
                        throw new NumberFormatException();
                    }
                    b = readByte();
                }
            }
            public int nextInt() {
                long nl = nextLong();
                if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
                return (int) nl;
            }
            public double nextDouble() { return Double.parseDouble(next());}
        }
}
