#include <iostream.h>
#include <fstream.h>
ifstream f("fact.in");
ofstream g("fact.out");
int main()
{long long k=0,i,p,nr;
f>>p;

for(i=5;k<p;i+=5)
{
nr=i;
while(nr%5==0) 
	{
	k++;
	nr=nr/5;
	}
}
if(p==0)g<<1;
if(k==p)g<<i-5;
	else g<<-1;
f.close();
g.close();
return 0;
}