#include<iostream.h>
#include<stdio.h>
int main()
{ long p, k=0;
unsigned ci, i;
freopen("fact.in", "rt", stdin);
freopen("fact.out", "wt", stdout);
cin>>p; if(!p) cout<<1;
else {
for(i=0,k=0;k<p;)
 if (p-k>4) {i+=20;k+=4;
	       i=i+5 ;
	       ci=i;
	       while(ci%5==0) {k++;ci/=5;}
	       }
   else {i+=(p-k)*5;k=p;}


if(k==p) cout<< i;
else  cout<< -1;
}
return 0;
}