#include <iostream>
#include <fstream>

using namespace std;

long factorial(int n) {
	if (n == 0 || n ==1)
		return 1;
	else return n * factorial(n-1);
}

long smallestNo(int p) {
	if (p == 0)
		return 1;

	long output = 0;
	long multipliesFound = 0;

	while (multipliesFound < p) {
		output++;

		if (output%625 == 0) {
			multipliesFound += 5;

			long temp = output/625;
			long multiplies = 0;
			while (temp%5 == 0) {
				multiplies++;
				temp = temp/5;
			}
			multipliesFound += multiplies;

		} else if (output%125==0) multipliesFound += 4;
		else if (output%25==0) multipliesFound += 3;
		else if (output%5==0) multipliesFound += 2;
		else multipliesFound += 1;
	}

	output *= 5;

	if (multipliesFound > p) output = -1;
	return output;
}

long pow5(long exp) {
	if (exp == 0) return 1;
	else return 5 * pow5(exp-1);
}

long factSearch(long p) {
	int k = 1;
	int sum = 1;
	int prevSum = 1;

	while (sum < p) {
		long aux = sum;
		sum = sum*5 + 1;
		prevSum = aux;
		k++;
		
	}
	
	long output = 0;
	if (sum == p) {
		output = pow5(k);
	} else output = pow5(k-1);
	
	
	if (sum != p) {
		long left = prevSum, right = sum;
		long step = sum;
		while (left != right && left < p && k > 0) {
			step = (step-1)/5;
			int bucket = (p-left)/step;
			k--;
			output += bucket * pow5(k);
			left = left + bucket*step;
			if (bucket == 5) 
				right = left + (bucket+1)*step+1;
			else right = left + (bucket+1)*step;

			//cout<<"step is: "<<step<<" bucket: "<<bucket<<" left: "<<left<<" right: "<<right<<endl;
		}

		if (left != right)
			output = -1;
	}

	
	//cout<<"res is: "<<output<<endl;
	return output;
}

int main(void) {
	ifstream f("fact.in");
	ofstream g("fact.out");
	long p;
	f>>p;
	long output = factSearch(p);
	g<<output;
	return 0;
}