#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <math.h>
#include <assert.h>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <string>
#include <functional>
#include <vector>
#include <deque>
#include <utility>
#include <bitset>
#include <limits.h>
#include <time.h>
using namespace std;
typedef long long ll;
typedef unsigned long long llu;
typedef double lf;
typedef unsigned int uint;
typedef long double llf;
typedef pair<int, int> pii;
int N, A[305];
int Table[305][205][205];
int solve (int x, int h1, int h2) {
if(x < 1 || h1 < 0 || h2 < 0) return 10000000;
if(x == 1) {
int h[] = {A[1], h1, h2};
int m = *min_element(h, h+3);
for(int i = 0; i < 3; i++) h[i] -= m;
for(int i = 0; i < 2; i++) if(h[i] > 0 && h[i+1] > 0) return 7*m + 5*min(h[i], h[i+1]) + 3*abs(h[i]-h[i+1]);
return 7*m + 3*(h[0]+h[1]+h[2]);
}
if(h2 == 0) return solve(x-1, A[x], h1);
int &ret = Table[x][h1][h2];
if(ret >= 0) return ret;
int candidates[] = {
solve(x, h1, h2-1) + 3,
solve(x, h1-1, h2-1) + 5,
solve(x-1, A[x] - h2, h1 - h2) + h2 * 7,
};
ret = *min_element(candidates, candidates+3);
return ret;
}
int main() {
int i, j, k;
scanf("%d", &N);
for(i = 1; i <= N; i++) scanf("%d", A+i);
if(N == 1) {
printf("%d\n", A[1] * 3);
return 0;
}
if(N == 2) {
int t = min(A[1], A[2]);
printf("%d\n", 5*t + 3*(A[1]-t+A[2]-t));
return 0;
}
memset(Table, -1, sizeof Table);
printf("%d\n", solve(N-2, A[N-1], A[N]));
return 0;
}
