#include<stdio.h>

long long int i,n,p,k;

int main(void)
{
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    scanf("%lli",&p);
    n=0;
    for(i=1;n<p;i++)
    {
       if(i%5==0)
       n++;
    }
   // printf("%i\n",i-1);
    if(n==p)
    {p=i-1;
    if(p>25)
    {k=p/25;
    i-=k*5;
     }   printf("%i",i-1);

    }
    else
    printf("-1");
  return 0;
}