#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll n, a, t=0;
int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin >> n;
	for (ll i = 1; i <= n; i++) {
		cin >> a;
		if(t%3==0){
			t+=(a>5)?((a/5*3)+((a%5>3)?(1+a%5-3):(a%5))):((a>3)?(1+a-3):1);
		}else{
			a-=3-t%3;
			t+=3-t%3+(a>5)?((a/5*3)+((a%5>3)?(1+a%5-3):(a%5))):((a>3)?(1+a-3):1);
		}
	}
	cout << t;
}

O(n)的递推式是什么啊？大佬救命