#include <fstream.h>

long p;
int main()
{
int k=0,i,ci;
ifstream in("fact.in");
ofstream out("fact.out");
in>>p;
for(i=5;k<=p;i=i+5)
{
	ci=i;
	while(ci%5==0 &&ci!=1)
	{
		k++;
		ci=ci/5;

	}
	if(k>=p)
        break;
}
out<<i;
return 0;
}