import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    long n;

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

    void run() {
        FastReader sc = new FastReader();
        n = sc.nextLong();
        solve();
    }

    void solve() {
        int sqrtN = (int)Math.sqrt(n) + 1;
        int minDigit = Integer.MAX_VALUE;
        for (long i = 1; i <= sqrtN; i++) {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        }
        System.out.println(minDigit);
    }

    int f(long a, long b) {
        int digitA = digit(a);
        int digitB = digit(b);
        if (digitA < digitB) {
            return digitB;
        }
        return digitA;
    }

    int digit(long a) {
        int ret = 0;
        for (; a > 0; ++ret) {
            a /= 10;
        }
        return ret;
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    long n;

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

    void run() {
        FastReader sc = new FastReader();
        n = sc.nextLong();
        solve();
    }

    void solve() {
        int sqrtN = (int)Math.sqrt(n) + 1;
        int minDigit = Integer.MAX_VALUE;
        for (long i = 1; i <= sqrtN; i++) {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        }
        System.out.println(minDigit);
    }

    int f(long a, long b) {
        int digitA = digit(a);
        int digitB = digit(b);
        if (digitA < digitB) {
            return digitB;
        }
        return digitA;
    }

    int digit(long a) {
        int ret = 0;
        for (; a > 0; ++ret) {
            a /= 10;
        }
        return ret;
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} Main long n; n public static void main(String args[]) {
        new Main().run();
    } main {
        new Main().run();
    } new Main().run() new Main().run new Main() String args[] args void run() {
        FastReader sc = new FastReader();
        n = sc.nextLong();
        solve();
    } run {
        FastReader sc = new FastReader();
        n = sc.nextLong();
        solve();
    } FastReader sc = new FastReader(); sc new FastReader() n = sc.nextLong() n sc.nextLong() sc.nextLong sc solve() solve void solve() {
        int sqrtN = (int)Math.sqrt(n) + 1;
        int minDigit = Integer.MAX_VALUE;
        for (long i = 1; i <= sqrtN; i++) {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        }
        System.out.println(minDigit);
    } solve {
        int sqrtN = (int)Math.sqrt(n) + 1;
        int minDigit = Integer.MAX_VALUE;
        for (long i = 1; i <= sqrtN; i++) {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        }
        System.out.println(minDigit);
    } int sqrtN = (int)Math.sqrt(n) + 1; sqrtN (int)Math.sqrt(n) + 1 (int)Math.sqrt(n) Math.sqrt Math n 1 int minDigit = Integer.MAX_VALUE; minDigit Integer.MAX_VALUE Integer Integer.MAX_VALUE for (long i = 1; i <= sqrtN; i++) {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        } long i = 1; long i = 1; i 1 i <= sqrtN i sqrtN i++ i++ i {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        } {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        } if (n % i > 0) {
                continue;
            } n % i > 0 n % i n i 0 {
                continue;
            } continue; long j = n / i; j n / i n i int digit = f(i, j); digit f(i, j) f i j if (digit < minDigit) {
                minDigit = digit;
            } digit < minDigit digit minDigit {
                minDigit = digit;
            } minDigit = digit minDigit digit System.out.println(minDigit) System.out.println System.out System System.out minDigit int f(long a, long b) {
        int digitA = digit(a);
        int digitB = digit(b);
        if (digitA < digitB) {
            return digitB;
        }
        return digitA;
    } f {
        int digitA = digit(a);
        int digitB = digit(b);
        if (digitA < digitB) {
            return digitB;
        }
        return digitA;
    } int digitA = digit(a); digitA digit(a) digit a int digitB = digit(b); digitB digit(b) digit b if (digitA < digitB) {
            return digitB;
        } digitA < digitB digitA digitB {
            return digitB;
        } return digitB; digitB return digitA; digitA long a a long b b int digit(long a) {
        int ret = 0;
        for (; a > 0; ++ret) {
            a /= 10;
        }
        return ret;
    } digit {
        int ret = 0;
        for (; a > 0; ++ret) {
            a /= 10;
        }
        return ret;
    } int ret = 0; ret 0 for (; a > 0; ++ret) {
            a /= 10;
        } ; a > 0 a 0 ++ret ++ret ret {
            a /= 10;
        } {
            a /= 10;
        } a /= 10 a 10 return ret; ret long a a static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        } FastReader {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        } br = new BufferedReader(new
                    InputStreamReader(System.in)) br new BufferedReader(new
                    InputStreamReader(System.in)) String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } next {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            } try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                } catch (IOException e)
                {
                    e.printStackTrace();
                } IOException e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    st = new StringTokenizer(br.readLine());
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt()
        {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong()
        {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble()
        {
            return Double.parseDouble(next());
        } nextDouble {
            return Double.parseDouble(next());
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        } nextLine {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        } String str = ""; str "" try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            } catch (IOException e)
            {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                str = br.readLine();
            } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
    long n;

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

    void run() {
        FastReader sc = new FastReader();
        n = sc.nextLong();
        solve();
    }

    void solve() {
        int sqrtN = (int)Math.sqrt(n) + 1;
        int minDigit = Integer.MAX_VALUE;
        for (long i = 1; i <= sqrtN; i++) {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        }
        System.out.println(minDigit);
    }

    int f(long a, long b) {
        int digitA = digit(a);
        int digitB = digit(b);
        if (digitA < digitB) {
            return digitB;
        }
        return digitA;
    }

    int digit(long a) {
        int ret = 0;
        for (; a > 0; ++ret) {
            a /= 10;
        }
        return ret;
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} public class Main {
    long n;

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

    void run() {
        FastReader sc = new FastReader();
        n = sc.nextLong();
        solve();
    }

    void solve() {
        int sqrtN = (int)Math.sqrt(n) + 1;
        int minDigit = Integer.MAX_VALUE;
        for (long i = 1; i <= sqrtN; i++) {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        }
        System.out.println(minDigit);
    }

    int f(long a, long b) {
        int digitA = digit(a);
        int digitB = digit(b);
        if (digitA < digitB) {
            return digitB;
        }
        return digitA;
    }

    int digit(long a) {
        int ret = 0;
        for (; a > 0; ++ret) {
            a /= 10;
        }
        return ret;
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    long n;

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

    void run() {
        FastReader sc = new FastReader();
        n = sc.nextLong();
        solve();
    }

    void solve() {
        int sqrtN = (int)Math.sqrt(n) + 1;
        int minDigit = Integer.MAX_VALUE;
        for (long i = 1; i <= sqrtN; i++) {
            if (n % i > 0) {
                continue;
            }
            long j = n / i;
            int digit = f(i, j);
            if (digit < minDigit) {
                minDigit = digit;
            }
        }
        System.out.println(minDigit);
    }

    int f(long a, long b) {
        int digitA = digit(a);
        int digitB = digit(b);
        if (digitA < digitB) {
            return digitB;
        }
        return digitA;
    }

    int digit(long a) {
        int ret = 0;
        for (; a > 0; ++ret) {
            a /= 10;
        }
        return ret;
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
}
