#include<fstream>
using namespace std;
ifstream fin("factorial.in");
ofstream fout("factorial.out");
int main()
{int p,i,k=0,ok=0,x,f;
fin>>p;
if(p!=0)
for(i=5;i<=500000000;i=i+5)
{
x=0;
f=i;
while(f%5==0)
{x++;
f=f/5;}
k=x+k;
if(k==p)
{ok=1;
break;
}
else
if(k>p)
    break;
}
if(ok==1 && p!=0)
    fout<<i;
else
    if(ok==0 && p!=0)
    fout<<-1;
else
    if(ok==0 && p==0)
    fout<<1;
}