#include <stdio.h>

int main()
{
    int p, nr, i, aux;

    FILE *fin = freopen("fact.in", "r", stdin);
    FILE *fout = freopen("fact.out", "w", stdout);

    scanf("%d", &p);

    for(i=5,nr=0;nr<p;i+=5)
    {
        aux = i;
        while(aux % 5 == 0) {
            nr++;
            aux /= 5;
        }
    }

    if(nr!=p)
    {
        printf("-1\n");
    }
    else
    {
        printf("%d\n", i-5);
    }
}