#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using T = tuple<ll, ll, ll>;
#define int long long
#define Base 41
#define sz(a) (int)a.size()
#define FOR(i, a, b) for ( int i = a ; i <= b ; i++ )
#define FORD(i, a, b) for (int i = b; i >= a; i --)
#define REP(i, n) for (int i = 0; i < n; ++i)
#define REPD(i, n) for (int i = n - 1; i >= 0; --i)
#define all(x) x.begin() , x.end()
#define pii pair<int , int>
#define fi first
#define se second
#define Lg(x) 31 - __builtin_clz(x)
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int MAX = 200 + 5;
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
void setupIO(){
#define name "Whisper"
//Phu Trong from Nguyen Tat Thanh High School for gifted student
srand(time(NULL));
cin.tie(nullptr)->sync_with_stdio(false); cout.tie(nullptr);
//freopen(name".inp", "r", stdin);
//freopen(name".out", "w", stdout);
cout << fixed << setprecision(10);
}
template <class X, class Y>
bool minimize(X &x, const Y &y){
X eps = 1e-9;
if (x > y + eps) {x = y; return 1;}
return 0;
}
template <class X, class Y>
bool maximize(X &x, const Y &y){
X eps = 1e-9;
if (x + eps < y) {x = y; return 1;}
return 0;
}
int N;
int a[305];
int dp[305][MAX][MAX];
//dp(i, h1, h2) xét đến vị trí i độ dài của (i - 1) và (i - 2) còn dư lại là h1 và h2
int f(int pos, int h1, int h2){
if (pos > N){
return min(h1, h2) * 5 + (max(h1, h2) - min(h1, h2)) * 3;
}
int &res = dp[pos][h1][h2];
if (~res) return res;
res = LINF;
int minHeight = min({h1, h2, a[pos]});
if (minHeight == h2){
minimize(res, f(pos + 1, a[pos] - h2, h1 - h2) + h2 * 7);
}
if (min(h1, h2) > 0){
minimize(res, f(pos, h1 - 1, h2 - 1) + 5);
}
if (h2){
minimize(res, f(pos, h1, h2 - 1) + 3);
}
return res;
}
void Whisper(){
cin >> N;
for (int i = 1; i <= N; ++i) cin >> a[i];
//nhận xét 1: càng sơn nhiều thằng 1 lúc càng tối ưu
memset(dp, -1, sizeof dp);
cout << f(3, a[2], a[1]);
}
signed main(){
setupIO();
int Test = 1;
// cin >> Test;
for ( int i = 1 ; i <= Test ; i++ ){
Whisper();
if (i < Test) cout << '\n';
}
}
