import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            long n = in.nextLong();
            int res = digits(n);
            for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            }
            out.println(res);
        }

        private int digits(long cur) {
            int digs = 0;
            while (cur > 0) {
                cur /= 10;
                ++digs;
            }
            return digs;
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

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

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

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.StringTokenizer; StringTokenizer java.util import java.io.IOException; IOException java.io import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.InputStream; InputStream java.io public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            long n = in.nextLong();
            int res = digits(n);
            for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            }
            out.println(res);
        }

        private int digits(long cur) {
            int digs = 0;
            while (cur > 0) {
                cur /= 10;
                ++digs;
            }
            return digs;
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

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

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

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) TaskC solver = new TaskC(); solver new TaskC() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            long n = in.nextLong();
            int res = digits(n);
            for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            }
            out.println(res);
        }

        private int digits(long cur) {
            int digs = 0;
            while (cur > 0) {
                cur /= 10;
                ++digs;
            }
            return digs;
        }

    } TaskC public void solve(int testNumber, InputReader in, PrintWriter out) {
            long n = in.nextLong();
            int res = digits(n);
            for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            }
            out.println(res);
        } solve {
            long n = in.nextLong();
            int res = digits(n);
            for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            }
            out.println(res);
        } long n = in.nextLong(); n in.nextLong() in.nextLong in int res = digits(n); res digits(n) digits n for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            } long i = 1L; long i = 1L; i 1L i * i <= n i * i i i n ++i ++i i {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            } {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            } if (n % i != 0) continue; n % i != 0 n % i n i 0 continue; long cur = n / i; cur n / i n i res = Math.min(res, Math.max(digits(i), digits(cur))) res Math.min(res, Math.max(digits(i), digits(cur))) Math.min Math res Math.max(digits(i), digits(cur)) Math.max Math digits(i) digits i digits(cur) digits cur out.println(res) out.println out res int testNumber testNumber InputReader in in PrintWriter out out private int digits(long cur) {
            int digs = 0;
            while (cur > 0) {
                cur /= 10;
                ++digs;
            }
            return digs;
        } digits {
            int digs = 0;
            while (cur > 0) {
                cur /= 10;
                ++digs;
            }
            return digs;
        } int digs = 0; digs 0 while (cur > 0) {
                cur /= 10;
                ++digs;
            } cur > 0 cur 0 {
                cur /= 10;
                ++digs;
            } cur /= 10 cur 10 ++digs digs return digs; digs long cur cur static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

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

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

    } InputReader public BufferedReader reader; reader public StringTokenizer tokenizer; tokenizer public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } InputReader {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } next {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } while (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 long nextLong() {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            long n = in.nextLong();
            int res = digits(n);
            for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            }
            out.println(res);
        }

        private int digits(long cur) {
            int digs = 0;
            while (cur > 0) {
                cur /= 10;
                ++digs;
            }
            return digs;
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

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

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

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            long n = in.nextLong();
            int res = digits(n);
            for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            }
            out.println(res);
        }

        private int digits(long cur) {
            int digs = 0;
            while (cur > 0) {
                cur /= 10;
                ++digs;
            }
            return digs;
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

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

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

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            long n = in.nextLong();
            int res = digits(n);
            for (long i = 1L; i * i <= n; ++i) {
                if (n % i != 0) continue;
                long cur = n / i;
                res = Math.min(res, Math.max(digits(i), digits(cur)));
            }
            out.println(res);
        }

        private int digits(long cur) {
            int digs = 0;
            while (cur > 0) {
                cur /= 10;
                ++digs;
            }
            return digs;
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

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

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

    }
}

