import java.util.*;

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

        long answer = n;

        for(long i = 1; i <= Math.sqrt(n); i++){
          if(n % i != 0) continue;
          long len1 = String.valueOf(i).length();
          long len2 = String.valueOf(n / i).length();
          answer = Math.min(answer, Math.max(len1, len2));
        }

        System.out.println(answer);
	}
}
/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