#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
#define ld long double
// 217
// 44
using namespace std;
const int MAXN = 300;
const int MAXH = 200;
int dp[MAXN + 1][MAXH + 1][MAXH + 1];
bool vis[MAXN + 1][MAXH + 1][MAXH + 1];
int h[MAXN + 1], n;
int solve(int pos, int h1, int h2) {
if(pos == n + 1) {
return 0;
}
if(vis[pos][h1][h2]) {
return dp[pos][h1][h2];
}
vis[pos][h1][h2] = 1;
if(h1 > 0) {
dp[pos][h1][h2] = solve(pos, h1 - 1, h2) + 3;
if(h2 > 0) {
dp[pos][h1][h2] = min(dp[pos][h1][h2], solve(pos, h1 - 1, h2 - 1) + 5);
}
if(pos < n) {
int mn = min(h1, min(h2, h[pos + 2]));
if(mn == h1)
dp[pos][h1][h2] = min(dp[pos][h1][h2], solve(pos + 1, h2 - mn, h[pos + 2] - mn) + 7 * mn);
}
}
else {
dp[pos][h1][h2] = solve(pos + 1, h2, h[pos + 2]);
}
return dp[pos][h1][h2];
}
int main() {
//ifstream cin("A.in");
//ofstream cout("A.out");
int i;
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin >> n;
for(i = 1; i <= n; i++) {
cin >> h[i];
}
cout << solve(1, h[1], h[2]);
//cin.close();
//cout.close();
return 0;
}
