#include<fstream.h>
ifstream f("fact.in");
ofstream g("fact.out");
int main(void)
{
 unsigned long i,p,ok=1,nr=0;
 f>>p;
 if(p==0) cout<<"1";
   else
    {
      for(i=5;ok&&nr<p ;i+=5)
	{
	  int d=i;
	     while(d!=0)
		      {
			 if(d%5==0) nr++; d=d/5;
		      }
	     if(p==nr) {ok=0; g<<i;}
	}
    }
 return 0;
}