//看看会不会爆int!数组会不会少了一维！

//取物问题一定要小心先手胜利的条件

#include <bits/stdc++.h>

using namespace std;

#pragma comment(linker,"/STACK:102400000,102400000")

#define LL long long

#define ALL(a) a.begin(), a.end()

#define pb push_back

#define mk make_pair

#define fi first

#define se second

#define haha printf("haha\n")

/*

定义：dp(x, y, t, dir = 8)，当前在坐标(x, y)这个位置，朝向为dir，将要从这点开始走t步（假定，向上是+，向下是-.），是否走过这个状态

*/

const int maxpos =  + ;

int dp[maxpos][maxpos][][];

int color[maxpos][maxpos];

int n;

int t[maxpos];

pair<int, int> dir[];

void init(){

    cin >> n;

    for (int i = ; i <= n; i++){

        scanf("%d", t + i);

    }

    ///逆时针标号

    dir[] = mk(, ), dir[] = mk(, ), dir[] = mk(-, ), dir[] = mk(-, );

    dir[] = mk(-, -), dir[] = mk(, -), dir[] = mk(, -), dir[] = mk(, );

}

struct Point{

    int x, y, aim;

};

int bfs(){

    if (n == ) return t[];

    t[n + ] = ;

    int x = , y = ;

    //dp[x][y + 1][t[1] - 1][1] = 1;

    queue<Point> que;

    for (int i = ; i <= t[]; i++){

        int nx = dir[].fi + x, ny = dir[].se + y;

        color[nx][ny] = ;

        x = nx, y = ny;

    }

    //printf("x = %d y = %d\n", x, y);

    que.push(Point{x, y, });

    que.push(Point{x, y, });

    dp[x][y][][] = ;

    dp[x][y][][] = ;

    for (int i = ; i <= n; i++){

        queue<Point> tmp;

        while (!que.empty()){

            Point from = que.front(); que.pop();

            //printf("%d %d\n", from.x, from.y);

            for (int j = ; j <= t[i]; j++){

                int nx = from.x + dir[from.aim].fi, ny = from.y + dir[from.aim].se;

                color[nx][ny] = ;

                from.x = nx, from.y = ny;

                //printf("nx = %d ny = %d\n", nx, ny);

            }

            int lb = (from.aim + ) % , rb = (from.aim -  + ) % ;

            if (dp[from.x][from.y][i][lb] == ){

                tmp.push(Point{from.x, from.y, lb});

                dp[from.x][from.y][i][lb] = ;

            }

            if (dp[from.x][from.y][i][rb] == ){

                tmp.push(Point{from.x, from.y, rb});

                dp[from.x][from.y][i][rb] = ;

            }

        }

        que = tmp;

    }

    int ans = ;

    for (int i = ; i < ; i++){

        for (int j = ; j < ; j++){

            ans += color[i][j];

            //if (color[i][j]) printf("x = %d y = %d\n", i, j);

        }

    }

    return ans;

}

int main(){

    init();

    printf("%d\n", bfs());

    return ;

}