import java.util.Scanner;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    int ans = 11;
    for(int i = 1; i <= Math.sqrt(n); i++){
      if(n%i == 0){
        long j= n/i;
        int temp = Math.max(String.valueOf(i).length(),String.valueOf(j).length());
        if(temp < ans){
          ans = temp;
        }
      }
    }
    System.out.println(ans);
  }
}
/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