using namespace std;
#include<cstdio>
unsigned long nr,x;
long p;



int main()
{
    freopen("fact.in","r",stdin);
   freopen("fact.out","w",stdout);
    scanf("%li",&p);
	if (!p) printf("1\n");
    while(p>0)
            {
            nr++;
            p--; ;
            x=nr;
            while(x%5==0) {p--; x=x/5;}
            }
    if(p==0)
    printf("%li\n",nr*5);
    else printf("-1\n");
}