import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		long n = in.nextLong();
		long res = Long.MAX_VALUE;
		for (long i = 1; i*i <= n; i++) {
			if (n % i == 0) {
				int tmpRes = 
						Math.max(
								String.valueOf(i).length(), 
								String.valueOf(n / i).length());
				res = Math.min(tmpRes, res);
			}
		}
		System.out.println(res);
	}
}
/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