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

public class Main {
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		long n = sc.nextLong();
		int res = Integer.MAX_VALUE;
		
		for (long i = 1; i <= (long)Math.sqrt(n*1.0); i++) {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		}
		
		System.out.println(res);
	}
  
	private static int F(long a, long b) {
		return Math.max(findDigit(a), findDigit(b));
	}
	
	private static int findDigit(long num) {
		int n = 0;
		while (num != 0) {
			n++;
			num /= 10;
		}
		return n;
	}
	
    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.Arrays; Arrays java.util import java.util.StringTokenizer; StringTokenizer java.util public class Main {
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		long n = sc.nextLong();
		int res = Integer.MAX_VALUE;
		
		for (long i = 1; i <= (long)Math.sqrt(n*1.0); i++) {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		}
		
		System.out.println(res);
	}
  
	private static int F(long a, long b) {
		return Math.max(findDigit(a), findDigit(b));
	}
	
	private static int findDigit(long num) {
		int n = 0;
		while (num != 0) {
			n++;
			num /= 10;
		}
		return n;
	}
	
    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 public static void main(String[] args) {
		FastReader sc = new FastReader();
		long n = sc.nextLong();
		int res = Integer.MAX_VALUE;
		
		for (long i = 1; i <= (long)Math.sqrt(n*1.0); i++) {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		}
		
		System.out.println(res);
	} main {
		FastReader sc = new FastReader();
		long n = sc.nextLong();
		int res = Integer.MAX_VALUE;
		
		for (long i = 1; i <= (long)Math.sqrt(n*1.0); i++) {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		}
		
		System.out.println(res);
	} FastReader sc = new FastReader(); sc new FastReader() long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc int res = Integer.MAX_VALUE; res Integer.MAX_VALUE Integer Integer.MAX_VALUE for (long i = 1; i <= (long)Math.sqrt(n*1.0); i++) {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		} long i = 1; long i = 1; i 1 i <= (long)Math.sqrt(n*1.0) i (long)Math.sqrt(n*1.0) Math.sqrt Math n*1.0 n 1.0 i++ i++ i {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		} {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		} if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} n % i == 0 n % i n i 0 {
				res = Math.min(res, F(i, n/i));
			} res = Math.min(res, F(i, n/i)) res Math.min(res, F(i, n/i)) Math.min Math res F(i, n/i) F i n/i n i System.out.println(res) System.out.println System.out System System.out res String[] args args private static int F(long a, long b) {
		return Math.max(findDigit(a), findDigit(b));
	} F {
		return Math.max(findDigit(a), findDigit(b));
	} return Math.max(findDigit(a), findDigit(b)); Math.max(findDigit(a), findDigit(b)) Math.max Math findDigit(a) findDigit a findDigit(b) findDigit b long a a long b b private static int findDigit(long num) {
		int n = 0;
		while (num != 0) {
			n++;
			num /= 10;
		}
		return n;
	} findDigit {
		int n = 0;
		while (num != 0) {
			n++;
			num /= 10;
		}
		return n;
	} int n = 0; n 0 while (num != 0) {
			n++;
			num /= 10;
		} num != 0 num 0 {
			n++;
			num /= 10;
		} n++ n num /= 10 num 10 return n; n long num num 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 {
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		long n = sc.nextLong();
		int res = Integer.MAX_VALUE;
		
		for (long i = 1; i <= (long)Math.sqrt(n*1.0); i++) {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		}
		
		System.out.println(res);
	}
  
	private static int F(long a, long b) {
		return Math.max(findDigit(a), findDigit(b));
	}
	
	private static int findDigit(long num) {
		int n = 0;
		while (num != 0) {
			n++;
			num /= 10;
		}
		return n;
	}
	
    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 {
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		long n = sc.nextLong();
		int res = Integer.MAX_VALUE;
		
		for (long i = 1; i <= (long)Math.sqrt(n*1.0); i++) {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		}
		
		System.out.println(res);
	}
  
	private static int F(long a, long b) {
		return Math.max(findDigit(a), findDigit(b));
	}
	
	private static int findDigit(long num) {
		int n = 0;
		while (num != 0) {
			n++;
			num /= 10;
		}
		return n;
	}
	
    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.Arrays;
import java.util.StringTokenizer;

public class Main {
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		long n = sc.nextLong();
		int res = Integer.MAX_VALUE;
		
		for (long i = 1; i <= (long)Math.sqrt(n*1.0); i++) {
			if (n % i == 0) {
				res = Math.min(res, F(i, n/i));
			} 
		}
		
		System.out.println(res);
	}
  
	private static int F(long a, long b) {
		return Math.max(findDigit(a), findDigit(b));
	}
	
	private static int findDigit(long num) {
		int n = 0;
		while (num != 0) {
			n++;
			num /= 10;
		}
		return n;
	}
	
    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;
	      }
	  }
}
