import java.io.*;
import java.util.*;

class Main {
  public static void main (String[] args) {
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    long min = 100000000;
    for(long i = 1; i*i <= n; i++) {
      if(n % i == 0) {
        long j = n/i;
        int F = Math.max(Long.toString(i).length(), Long.toString(j).length());
        min = Math.min(min, F);
      }
    }
    System.out.println(min);
  }
}

/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