import java.util.Scanner;

public class Main {


    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        int answer = Integer.MAX_VALUE;
        for (long i = 1; i*i <= N; i++) {
            if (N % i == 0) {
                int F = Math.max(digitLength(i), digitLength(N / i));
                if (answer > F) {
                    answer = F;
                }
            }
        }

        System.out.println(answer);

    }

    private static int digitLength(long i) {
        return Long.toString(i).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