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int t[MAXn + 10][MAXn + 10];
inline int lowbit(int x) {
    return x & (-x);
}
inline void Add(int x, int y, int k, int topx, int topy) {
    for (int i = x; i <= topx; i += lowbit(i)) {
        for (int j = y; j <= topy; j += lowbit(j)) {
            t[i][j] += k;
        }
    }
}
inline int Sum(int x, int y) {
    int ans = 0;
    for (int i = x; i; i -= lowbit(i)) {
        for (int j = y; j; j -= lowbit(j)) {
            ans += t[i][j];
        }
    }
    return ans;
}
inline int Sec(int x1, int y1, int x2, int y2) {
    return Sum(x2, y2) - Sum(x1 - 1, y2) - Sum(x2, y1 - 1) + Sum(x1 - 1, y1 - 1);
}