#include<bits/stdc++.h>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
typedef long long ll;




int main()
{
    cin.tie(0);
    ios_base::sync_with_stdio(0);
    cout.tie(0);

    ll n;in>>n;
    ll i=5;
    if(n==0)return out<<"1",0;
    while(n>0){
       ll x=i;
       int sum=0;
       while(x%5==0)++sum,x/=5;
       n-=sum;
       i+=5;
    }
    if(n==0)out<<i-5<<'\n';
    else out<<"-1";



    return 0;
}