#include <cstdio>
using namespace std;
int p,nr;
unsigned long int n,k;
int main()
{
freopen("fact.in","r",stdin);
freopen("fact.out","w",stdout);
scanf("%d",&p);
if (p==0) printf("1");
     else {
           while (nr<p)
               {
               n+=5;k=n;
               while (k%5==0) {
                              k/=5;
                              nr++;
                              }
               }
          if (nr==p) printf("%d",n);
          }
}