
import java.util.Scanner;

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

/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