import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong();
		sc.close();
		
		long k = (int) Math.sqrt(N);
		while(N%k!=0){
			k--;
		}
		System.out.println(func(k,N/k));

	}
	
	public static int func(long a, long b){
		return Math.max(String.valueOf(a).length(), String.valueOf(b).length());
	}

}
/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