import java.util.Scanner;

/**
 * https://abc057.contest.atcoder.jp/tasks/abc057_c
 */
public class Main {

	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong();
		sc.close();
		
		long a = (int) Math.sqrt(N)+1;
		long b = 0;
		for(long i=a; i>=1; i--){
			if(N%i==0){
				a=i;
				b=N/i;
				break;
			}
		}
		
		System.out.println(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