#include <iostream>
#include <cstdio>
#define MAXVAL 0x3fffffff

using namespace std;

int zeros(int val)
{
	int rez = 0;
    for (int i = 5; i <= val; i*=5)
		rez += val / i;
	return rez;
}

int main()
{
    freopen("fact.in", "r", stdin);
    freopen("fact.out", "w", stdout);

	int p;
    scanf("%d", &p);
    int step;
    for (step = 1; step < MAXVAL; step <<= 1);
    int rez = MAXVAL, aux;
    for (int i = 1; step; step >>= 1)
        if (rez - step > 0 && zeros(rez - step) >= p)
            rez -= step;
	if (zeros(rez) == p)
		printf("%d", rez);
	else
		printf("%d", -1);

    return 0;
}