#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<int> h(n);
for (int i = 0; i < n; i++) {
cin >> h[i];
}
if (n == 1) {
cout << 3 * h[0] << '\n';
return 0;
}
const int MAX = 202;
const int inf = (int) 1e9;
vector<vector<int>> dp(MAX, vector<int>(MAX, inf));
dp[0][0] = 0;
for (int i = 0; i < n; i++) {
int x = (i >= 2 ? h[i - 2] : 0);
int y = (i >= 1 ? h[i - 1] : 0);
vector<vector<int>> new_dp(MAX, vector<int>(MAX, inf));
for (int a = 0; a <= x; a++) {
for (int b = 0; b <= y; b++) {
if (dp[a][b] == inf) {
continue;
}
for (int three = 0; three <= min({x - a, y - b, h[i]}); three++) {
for (int two = min({x - a, y - b}) - three; two <= min({x - a, y - b}) - three; two++) {
int ta = a + three + two;
int tb = b + three + two;
int tc = three;
new_dp[tb][tc] = min(new_dp[tb][tc], dp[a][b] + three * 7 + two * 5 + (x - ta) * 3);
}
}
/* int ta = a, tb = b, tc = 0;
int ft = dp[a][b];
{
int v = min({x - ta, y - tb, h[i] - tc});
ta += v;
tb += v;
tc += v;
ft += 7 * v;
}
{
int v = min({x - ta, y - tb});
ta += v;
tb += v;
ft += 5 * v;
}
{
int v = x - ta;
ta += v;
ft += 3 * v;
}
new_dp[tb][tc] = min(new_dp[tb][tc], ft); */
}
}
swap(dp, new_dp);
}
int res = inf;
int x = h[n - 2];
int y = h[n - 1];
for (int a = 0; a <= x; a++) {
for (int b = 0; b <= y; b++) {
if (dp[a][b] == inf) {
continue;
}
int ta = a, tb = b;
int ft = dp[a][b];
{
int v = min({x - ta, y - tb});
ta += v;
tb += v;
ft += 5 * v;
}
{
int v = max({x - ta, y - tb});
ft += 3 * v;
}
res = min(res, ft);
}
}
cout << res << '\n';
return 0;
}
