import java.io.*;
import java.util.*;
import java.lang.Math.*;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        long N = scanner.nextLong();
        List<Long> list = new ArrayList<>();
        long ans = ("" + N).length();
        for (long i = 1; i * i <= N; i++) {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        }

        System.out.println(ans);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";

        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public String next() throws IOException {
            if (i < s.length) return s[i++];
            String line = br.readLine();
            while (line.equals("")) {
                line = br.readLine();
            }
            s = line.split(reg, 0);
            i = 0;
            return s[i++];
        }

        public int nextInt() {
            try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public double nextDouble() {
            try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public long nextLong()  {
            try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }
    }
} import java.io.*; io.* java import java.util.*; util.* java import java.lang.Math.*; Math.* java.lang public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        long N = scanner.nextLong();
        List<Long> list = new ArrayList<>();
        long ans = ("" + N).length();
        for (long i = 1; i * i <= N; i++) {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        }

        System.out.println(ans);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";

        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public String next() throws IOException {
            if (i < s.length) return s[i++];
            String line = br.readLine();
            while (line.equals("")) {
                line = br.readLine();
            }
            s = line.split(reg, 0);
            i = 0;
            return s[i++];
        }

        public int nextInt() {
            try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public double nextDouble() {
            try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public long nextLong()  {
            try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }
    }
} Main public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    } main {
        Main main = new Main();
        main.solve(args);
    } Main main = new Main(); main new Main() main.solve(args) main.solve main args String[] args args public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        long N = scanner.nextLong();
        List<Long> list = new ArrayList<>();
        long ans = ("" + N).length();
        for (long i = 1; i * i <= N; i++) {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        }

        System.out.println(ans);
    } solve {
        MyScanner scanner = new MyScanner();
        long N = scanner.nextLong();
        List<Long> list = new ArrayList<>();
        long ans = ("" + N).length();
        for (long i = 1; i * i <= N; i++) {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        }

        System.out.println(ans);
    } MyScanner scanner = new MyScanner(); scanner new MyScanner() long N = scanner.nextLong(); N scanner.nextLong() scanner.nextLong scanner List<Long> list = new ArrayList<>(); list new ArrayList<>() long ans = ("" + N).length(); ans ("" + N).length() ("" + N).length ("" + N) "" N for (long i = 1; i * i <= N; i++) {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        } long i = 1; long i = 1; i 1 i * i <= N i * i i i N i++ i++ i {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        } {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        } if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            } N % i == 0 N % i N i 0 {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            } long b = N / i; b N / i N i long c = Math.max(("" + i).length(), ("" + b).length()); c Math.max(("" + i).length(), ("" + b).length()) Math.max Math ("" + i).length() ("" + i).length ("" + i) "" i ("" + b).length() ("" + b).length ("" + b) "" b ans = Math.min(c, ans) ans Math.min(c, ans) Math.min Math c ans System.out.println(ans) System.out.println System.out System System.out ans String[] args args private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";

        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public String next() throws IOException {
            if (i < s.length) return s[i++];
            String line = br.readLine();
            while (line.equals("")) {
                line = br.readLine();
            }
            s = line.split(reg, 0);
            i = 0;
            return s[i++];
        }

        public int nextInt() {
            try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public double nextDouble() {
            try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public long nextLong()  {
            try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }
    } MyScanner String[] s; s int i; i BufferedReader br; br String reg = " "; reg " " MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        } MyScanner {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        } s = new String[0] s new String[0] 0 i = 0 i 0 br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) public String next() throws IOException {
            if (i < s.length) return s[i++];
            String line = br.readLine();
            while (line.equals("")) {
                line = br.readLine();
            }
            s = line.split(reg, 0);
            i = 0;
            return s[i++];
        } next {
            if (i < s.length) return s[i++];
            String line = br.readLine();
            while (line.equals("")) {
                line = br.readLine();
            }
            s = line.split(reg, 0);
            i = 0;
            return s[i++];
        } if (i < s.length) return s[i++]; i < s.length i s.length s s.length return s[i++]; s[i++] s i++ i String line = br.readLine(); line br.readLine() br.readLine br while (line.equals("")) {
                line = br.readLine();
            } line.equals("") line.equals line "" {
                line = br.readLine();
            } line = br.readLine() line br.readLine() br.readLine br s = line.split(reg, 0) s line.split(reg, 0) line.split line reg 0 i = 0 i 0 return s[i++]; s[i++] s i++ i public int nextInt() {
            try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        } nextInt {
            try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        } try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            } Exception e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                return Integer.parseInt(next());
            } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next return -1; -1 1 public double nextDouble() {
            try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        } nextDouble {
            try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        } try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            } Exception e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                return Double.parseDouble(next());
            } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next return -1; -1 1 public long nextLong()  {
            try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        } nextLong {
            try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        } try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            } Exception e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                return Long.parseLong(next());
            } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next return -1; -1 1 public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        long N = scanner.nextLong();
        List<Long> list = new ArrayList<>();
        long ans = ("" + N).length();
        for (long i = 1; i * i <= N; i++) {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        }

        System.out.println(ans);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";

        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public String next() throws IOException {
            if (i < s.length) return s[i++];
            String line = br.readLine();
            while (line.equals("")) {
                line = br.readLine();
            }
            s = line.split(reg, 0);
            i = 0;
            return s[i++];
        }

        public int nextInt() {
            try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public double nextDouble() {
            try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public long nextLong()  {
            try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }
    }
} public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        long N = scanner.nextLong();
        List<Long> list = new ArrayList<>();
        long ans = ("" + N).length();
        for (long i = 1; i * i <= N; i++) {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        }

        System.out.println(ans);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";

        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public String next() throws IOException {
            if (i < s.length) return s[i++];
            String line = br.readLine();
            while (line.equals("")) {
                line = br.readLine();
            }
            s = line.split(reg, 0);
            i = 0;
            return s[i++];
        }

        public int nextInt() {
            try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public double nextDouble() {
            try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public long nextLong()  {
            try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }
    }
} Main
import java.io.*;
import java.util.*;
import java.lang.Math.*;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        long N = scanner.nextLong();
        List<Long> list = new ArrayList<>();
        long ans = ("" + N).length();
        for (long i = 1; i * i <= N; i++) {
            if (N % i == 0) {
                long b = N / i;
                long c = Math.max(("" + i).length(), ("" + b).length());
                ans = Math.min(c, ans);
            }
        }

        System.out.println(ans);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";

        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public String next() throws IOException {
            if (i < s.length) return s[i++];
            String line = br.readLine();
            while (line.equals("")) {
                line = br.readLine();
            }
            s = line.split(reg, 0);
            i = 0;
            return s[i++];
        }

        public int nextInt() {
            try {
                return Integer.parseInt(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public double nextDouble() {
            try {
                return Double.parseDouble(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }

        public long nextLong()  {
            try {
                return Long.parseLong(next());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return -1;
        }
    }
}
