#include<iostream>
#include<cmath>

using namespace std;

int n;
int dp[1000005];
int main(){
    cin >> n;
    dp[0] = 0;
    for(int i = 1; i <= n; i++){
        if(i >= 1) dp[i] = min(dp[i],dp[i - 1] + 1);
        if(i >= 5) dp[i] = min(dp[i],dp[i - 5] + 1);
        if(i >= 11) dp[i] = min(dp[i],dp[i - 11] + 1);
    }
    cout << dp[n] << endl;
    return 0;
}