#include <cstdio>
#include <algorithm>
using namespace std;
int nr2,p,nr5,i,nr22,nr55;
long long x,n;
int fact(int x){
while(x%2==0 && x!=0){nr2++;x/=2;}
while(x%5==0 && x!=0){nr55++;x/=5;}
}
int fact1(int x){
while(x%5==0 && x!=0){nr5++;x/=5;}
while(x%2==0 && x!=0){nr22++;x/=2;}
}
int main()
{freopen("fact.in","r",stdin);
freopen("fact.out","w",stdout);
scanf("%d",&p);
if(p==0)printf("1");
else{
n=0;
while(nr2<p){
n++;fact(n);
}
x=0;
while(nr5<p){
x++;
fact1(x);
}
if(nr2==p && nr55>=p)printf("%d",n);
else if(nr5==p && nr22>=p)printf("%d",x);
else if(p!=0)printf("-1");
}
    return 0;
}