n! = n × (n − 1) × (n − 2) × ... × 3 × 2 × 1

Is called the factorial of n. For example, the factorial of 12

12! = 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 479001600

And there are two consecutive 0s at the end.

Write a program that inputs the integer n and outputs the number of consecutive 0s at the end of n !. However, n is a positive integer less than or equal to 20000.



Input

Multiple data are given. Each piece of data is given n (n ≤ 20000) on one line. When n is 0, it is the last input.

The number of data does not exceed 20.

Output

For each data, output the number of 0s that are consecutively arranged at the end of n! On one line.

Example

Input

2
12
10000
0


Output

0
2
2499
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.NoSuchElementException;
import java.util.Scanner;

public class Main {
	int N;
	
	public void solve() {
		while(true){
			int two = 0;
			int five = 0;
			N = nextInt();
			if(N==0)break;
			for(int i = N;i >= 2;i--){
				int j = i;
				while(j%2==0){
					j/=2;
					two++;
				}
				
				while(j%5==0){
					j/=5;
					five++;
				}
			}
			
			out.println(Math.min(two,five));
		}
	}
 
	public static void main(String[] args) {
		out.flush();
		new Main().solve();
		out.close();
	}
		/* Input */
	private static final InputStream in = System.in;
	private static final PrintWriter out = new PrintWriter(System.out);
	private final byte[] buffer = new byte[2048];
	private int p = 0;
	private int buflen = 0;

	private boolean hasNextByte() {
		if (p < buflen)
			return true;
		p = 0;
		try {
			buflen = in.read(buffer);
		} catch (IOException e) {
			e.printStackTrace();
		}
		if (buflen <= 0)
			return false;
		return true;
	}

	public boolean hasNext() {
		while (hasNextByte() && !isPrint(buffer[p])) {
			p++;
		}
		return hasNextByte();
	}

	private boolean isPrint(int ch) {
		if (ch >= '!' && ch <= '~')
			return true;
		return false;
	}

	private int nextByte() {
		if (!hasNextByte())
			return -1;
		return buffer[p++];
	}

	public String next() {
		if (!hasNext())
			throw new NoSuchElementException();
		StringBuilder sb = new StringBuilder();
		int b = -1;
		while (isPrint((b = nextByte()))) {
			sb.appendCodePoint(b);
		}
		return sb.toString();
	}

	public int nextInt() {
		return Integer.parseInt(next());
	}

	public long nextLong() {
		return Long.parseLong(next());
	}

	public double nextDouble() {
		return Double.parseDouble(next());
	}
}