import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();

    int M = (int)  Math.sqrt( N ) + 1;

    int Fmin = String.valueOf(N).length();
    for(int i = 2 ; i <= M ; i ++){
      if( N % i == 0 ){
        long j = N / i ;
        int A = String.valueOf(i).length();
        int B = String.valueOf(j).length();
        int F = Math.max(A,B);
        if(Fmin > F){
          Fmin = F ;
        }
      }
    }
    System.out.println(Fmin);
  }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz