#include<bits/stdc++.h>
using namespace std;
long long f[1000050];
int main(){
    long long n;
    cin>>n;
    for(long long i=1;i<=n;i++){
        f[i]=1145141919810;
        f[i]=min(f[i-1],f[i])+1;
        if(i>=5)f[i]=min(f[i-5],f[i])+1;
        if(i>=11)f[i]=min(f[i-11],f[i])+1;
    }
    cout<<f[n];
    return 0;
}