#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;
bool done[301][201][201];
int val[301][201][201];
int n,h[303];
void tri(int& a, int b) { a = min(a,b); }
int get(int pos, int h1, int h2) {
if (pos == n+1) return 0;
if (done[pos][h1][h2]) return val[pos][h1][h2];
done[pos][h1][h2] = 1;
val[pos][h1][h2] = MOD;
if (h1) {
tri(val[pos][h1][h2],get(pos,h1-1,h2)+3);
if (h2) {
tri(val[pos][h1][h2],get(pos,h1-1,h2-1)+5);
if (h1 <= min(h2,h[pos+2])) tri(val[pos][h1][h2],get(pos+1,h2-h1,h[pos+2]-h1)+7*h1);
}
} else val[pos][h1][h2] = get(pos+1,h2,h[pos+2]);
return val[pos][h1][h2];
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n;
FOR(i,1,n+1) cin >> h[i];
cout << get(1,h[1],h[2]);
}
/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/
