import java.util.*;
import java.io.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner(System.in);
        long n = sc.nextLong();
        long sn = (long)Math.sqrt(n);
        long ans = Long.MAX_VALUE;
        for(long i = 1; i <= sn; i++){
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        }
        System.out.println(ans);
    }
}

class FastScanner {
    private BufferedReader reader = null;
    private StringTokenizer tokenizer = null;
    public FastScanner(InputStream in) {
        reader = new BufferedReader(new InputStreamReader(in));
        tokenizer = null;
    }

    public String next() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    }

    public String nextLine() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken("\n");
    }

    public long nextLong() {
        return Long.parseLong(next());
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

    public double nextDouble() {
         return Double.parseDouble(next());
    }

    public int[] nextIntArray(int n) {
        int[] a = new int[n];
        for (int i = 0; i < n; i++)
            a[i] = nextInt();
        return a;
    }

    public long[] nextLongArray(int n) {
        long[] a = new long[n];
        for (int i = 0; i < n; i++)
            a[i] = nextLong();
        return a;
    } 
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner(System.in);
        long n = sc.nextLong();
        long sn = (long)Math.sqrt(n);
        long ans = Long.MAX_VALUE;
        for(long i = 1; i <= sn; i++){
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner(System.in);
        long n = sc.nextLong();
        long sn = (long)Math.sqrt(n);
        long ans = Long.MAX_VALUE;
        for(long i = 1; i <= sn; i++){
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        }
        System.out.println(ans);
    } main {
        FastScanner sc = new FastScanner(System.in);
        long n = sc.nextLong();
        long sn = (long)Math.sqrt(n);
        long ans = Long.MAX_VALUE;
        for(long i = 1; i <= sn; i++){
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        }
        System.out.println(ans);
    } FastScanner sc = new FastScanner(System.in); sc new FastScanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc long sn = (long)Math.sqrt(n); sn (long)Math.sqrt(n) Math.sqrt Math n long ans = Long.MAX_VALUE; ans Long.MAX_VALUE Long Long.MAX_VALUE for(long i = 1; i <= sn; i++){
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        } long i = 1; long i = 1; i 1 i <= sn i sn i++ i++ i {
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        } {
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        } if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            } n % i == 0 n % i n i 0 {
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            } ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length())) ans Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length())) Math.min Math ans Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()) Math.max Math String.valueOf(i).length() String.valueOf(i).length String.valueOf(i) String.valueOf String i String.valueOf(n/i).length() String.valueOf(n/i).length String.valueOf(n/i) String.valueOf String n/i n i System.out.println(ans) System.out.println System.out System System.out ans String[] args args class FastScanner {
    private BufferedReader reader = null;
    private StringTokenizer tokenizer = null;
    public FastScanner(InputStream in) {
        reader = new BufferedReader(new InputStreamReader(in));
        tokenizer = null;
    }

    public String next() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    }

    public String nextLine() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken("\n");
    }

    public long nextLong() {
        return Long.parseLong(next());
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

    public double nextDouble() {
         return Double.parseDouble(next());
    }

    public int[] nextIntArray(int n) {
        int[] a = new int[n];
        for (int i = 0; i < n; i++)
            a[i] = nextInt();
        return a;
    }

    public long[] nextLongArray(int n) {
        long[] a = new long[n];
        for (int i = 0; i < n; i++)
            a[i] = nextLong();
        return a;
    } 
} FastScanner private BufferedReader reader = null; reader null private StringTokenizer tokenizer = null; tokenizer null public FastScanner(InputStream in) {
        reader = new BufferedReader(new InputStreamReader(in));
        tokenizer = null;
    } FastScanner {
        reader = new BufferedReader(new InputStreamReader(in));
        tokenizer = null;
    } reader = new BufferedReader(new InputStreamReader(in)) reader new BufferedReader(new InputStreamReader(in)) tokenizer = null tokenizer null InputStream in in public String next() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    } next {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    } if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        } try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            } catch (IOException e) {
                throw new RuntimeException(e);
            } IOException e {
                throw new RuntimeException(e);
            } throw new RuntimeException(e); new RuntimeException(e) {
                tokenizer = new StringTokenizer(reader.readLine());
            } tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer public String nextLine() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken("\n");
    } nextLine {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken("\n");
    } if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        } try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            } catch (IOException e) {
                throw new RuntimeException(e);
            } IOException e {
                throw new RuntimeException(e);
            } throw new RuntimeException(e); new RuntimeException(e) {
                return reader.readLine();
            } return reader.readLine(); reader.readLine() reader.readLine reader return tokenizer.nextToken("\n"); tokenizer.nextToken("\n") tokenizer.nextToken tokenizer "\n" public long nextLong() {
        return Long.parseLong(next());
    } nextLong {
        return Long.parseLong(next());
    } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public int nextInt() {
        return Integer.parseInt(next());
    } nextInt {
        return Integer.parseInt(next());
    } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next 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 int[] nextIntArray(int n) {
        int[] a = new int[n];
        for (int i = 0; i < n; i++)
            a[i] = nextInt();
        return a;
    } nextIntArray {
        int[] a = new int[n];
        for (int i = 0; i < n; i++)
            a[i] = nextInt();
        return a;
    } int[] a = new int[n]; a new int[n] n for (int i = 0; i < n; i++)
            a[i] = nextInt(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = nextInt(); a[i] = nextInt() a[i] a i nextInt() nextInt return a; a int n n public long[] nextLongArray(int n) {
        long[] a = new long[n];
        for (int i = 0; i < n; i++)
            a[i] = nextLong();
        return a;
    } nextLongArray {
        long[] a = new long[n];
        for (int i = 0; i < n; i++)
            a[i] = nextLong();
        return a;
    } long[] a = new long[n]; a new long[n] n for (int i = 0; i < n; i++)
            a[i] = nextLong(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = nextLong(); a[i] = nextLong() a[i] a i nextLong() nextLong return a; a int n n public class Main {
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner(System.in);
        long n = sc.nextLong();
        long sn = (long)Math.sqrt(n);
        long ans = Long.MAX_VALUE;
        for(long i = 1; i <= sn; i++){
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        }
        System.out.println(ans);
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner(System.in);
        long n = sc.nextLong();
        long sn = (long)Math.sqrt(n);
        long ans = Long.MAX_VALUE;
        for(long i = 1; i <= sn; i++){
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        }
        System.out.println(ans);
    }
} Main
import java.util.*;
import java.io.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner(System.in);
        long n = sc.nextLong();
        long sn = (long)Math.sqrt(n);
        long ans = Long.MAX_VALUE;
        for(long i = 1; i <= sn; i++){
            if(n % i == 0){
                ans = Math.min(ans, Math.max(String.valueOf(i).length(), String.valueOf(n/i).length()));
            }
        }
        System.out.println(ans);
    }
}

class FastScanner {
    private BufferedReader reader = null;
    private StringTokenizer tokenizer = null;
    public FastScanner(InputStream in) {
        reader = new BufferedReader(new InputStreamReader(in));
        tokenizer = null;
    }

    public String next() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    }

    public String nextLine() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken("\n");
    }

    public long nextLong() {
        return Long.parseLong(next());
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

    public double nextDouble() {
         return Double.parseDouble(next());
    }

    public int[] nextIntArray(int n) {
        int[] a = new int[n];
        for (int i = 0; i < n; i++)
            a[i] = nextInt();
        return a;
    }

    public long[] nextLongArray(int n) {
        long[] a = new long[n];
        for (int i = 0; i < n; i++)
            a[i] = nextLong();
        return a;
    } 
}
