import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		ABC057CSolve solve = new ABC057CSolve();
		solve.main();
	}
}

class ABC057CSolve {
	
	long N;
	
	ABC057CSolve() {
		Scanner cin = new Scanner(System.in);
		this.N = cin.nextLong();
	}
	
	void main() {
		long min = Long.MAX_VALUE / 2;
		if (N == 1) {
			System.out.println(1);
			return;
		}
		for (int i = 1; i <= Math.sqrt(N); i++) {
			if (N % i == 0) {
				long a = i;
				long b = N / i;
				long f = F(a, b);
				min = Math.min(min, f);
			}
		}
		System.out.println(min);
	}
	
	int F(long a, long b) {
		int aCount = String.valueOf(a).length();
		int bCount = String.valueOf(b).length();
		return aCount > bCount ? aCount : bCount;
	}

}

/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