#include<fstream> 
using namespace std; 
ifstream fin("fact.in");
ofstream fout("fact.out"); 
int main () 
{
    int x=0,p,k=0,n=0;
    fin >> p;
    if(p==0)fout<<"1";
    while(k<p)
	{
		x+=5;
		n=x;
		while(n%5==0)
		{
			n=n/5;
	        k++;
		}
    }
	fout<<x;
    fin.close();
    fout.close();
    return 0;
}