import java.util.*;

import static java.lang.System.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();

        // ルートN * ルートNのときが最も最小
        long divide1 = (long) Math.sqrt(N);

        while(N % divide1 != 0) {
            divide1--;
        }
        long divide2 = N / divide1;

        int len1 = String.valueOf(divide1).length();
        int len2 = String.valueOf(divide2).length();

        out.println(Math.max(len1, len2));
    }
}
/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