import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        final Scanner sc = new Scanner(System.in);

        final long N = sc.nextLong();

        long ans = Long.MAX_VALUE;

        for (int i = 1; i <= Math.sqrt(N); i++) {
            if ((i*(N/i)) == N) {
                ans = Math.min(ans, f(i, (int) (N/i)));
            }
        }

        System.out.println(ans);
    }

    private static int f(final int a, final int 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