import java.util.Scanner;

/**
 * Created by zzt on 17-3-26.
 */
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();

        int ret = String.valueOf(n).length();

        for (long i = 1; i <= n/i ; i++) {
            if (n%i==0) {
                ret = Math.min(ret, Math.max(String.valueOf(i).length(), String.valueOf(n / i).length()));
            }
        }
        System.out.println(ret);
    }
}
/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