import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		long n = sc.nextLong();
		int sqrt = (int) Math.floor(Math.sqrt(n));
		int min_Keta = String.valueOf(n).length();

		for (int i = 2; i <= sqrt ; i++){
			if (n % i == 0){
				min_Keta = Math.min(min_Keta, Math.max(String.valueOf(i).length(),String.valueOf(n / i).length()));
			}
		}

		System.out.println(min_Keta);
	}

}

/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