#include <cstdio>

using namespace std;
int n,p,x,q,i;
int main()
{
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    scanf("%d",&p);
    if(p==0)n=1;
    else {
           q=1;x=1;n=5;
               while(q<p)
               {    x++;
                   n=5*x;q++;
                   if(x%5==0)
                      for(i=5;i<=x;i*=5)
                      q++;
               }

    }
    printf("%d\n",n);

    return 0;
}