#include<fstream>
using namespace std;
int main ()
{unsigned n,b,p,c=0,k=0;
ifstream f("fact.in");
ofstream g("fact.out");
f>>p;
if(p==0)
c=1;
else
{do
{c=c+5;b=c;
while(b%5==0)
{k=k+1;
b=b/5;}}
while(k<p);
}
g<<c;
f.close();
g.close();
return 0;}