#include <iostream>
#include <fstream>
#include <math.h>
#define MAX 1e6

using namespace std;

ifstream in("fact.in");
ofstream out("fact.out");

//5 10 15 20
int P;
int all(int k){
    return k/5;
}



int zero(int k) {
	long long int sum = 0;
	while (k) {
		sum += k / 5;
		k /= 5;
	}
	return sum;
}
int F(int j){
    int aux = 0;
    if(j == 0){
        out<<1;
        return 1;
    }
    for(int i = 5 ; i < MAX; i += 5){
        if(zero(i) == j){
            out<<i;
            return i;
        }else if(zero(i) > j){
            out<<-1;
            return - 1;
        }
    }
}

int main()
{
    in>>P;
    F(P);

}