#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define f first
#define s second
#define pb push_back
#define ep emplace
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define uniquev(v) sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define mem(f,x) memset(f , x , sizeof(f))
#define sz(x) (ll)(x).size()
#define __lcm(a, b) (1ll * ((a) / __gcd((a), (b))) * (b))
#define mxx *max_element
#define mnn *min_element
#define cntbit(x) __builtin_popcountll(x)
#define len(x) (int)(x.length())
const int N = 400;
int a[N], n;
int f[301][201][201];
int cal(int id, int x, int y) {
if (id == n + 1) {
return 0;
}
if (f[id][x][y] != -1)
return f[id][x][y];
int ans = 1e9;
if (x == 0) {
return f[id][x][y] = cal(id + 1, y, a[id + 2]);
}
ans = cal(id, x - 1, y) + 3;
if (y)
ans = min(ans, cal(id, x - 1, y - 1) + 5);
if (x <= min(y, a[id + 2]))
ans = min(ans, cal(id + 1, y - x, a[id + 2] - x) + x * 7);
return f[id][x][y] = ans;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
mem(f, -1);
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> a[i];
}
cout << cal(1, a[1], a[2]) << '\n';
return 0;
}
