Python NZEC on KFORK but AC using C++

I was trying to solve the KFORK problem. I have a solution in C++ that I got AC with, but my identical Python3 solution gets an NZEC. I’m new to using Python on CodeChef, so maybe there is something basic I am missing. Can someone please take a look at the following code and see if something is wrong?


def is_X_Y_valid(board, X, Y):
    return (X >= 0 and X < len(board) and
            Y >= 0 and Y < len(board[X]))


T = int(input())

for _ in range(0, T):
    N, M = (int(i) for i in input().split())

    board = [[False] * N for x in range(N)]
    xAttacked = [False] * N
    yAttacked = [False] * N
    mainDiagAttacked = [False] * (2 * N - 1)
    offDiagAttacked = [False] * (2 * N - 1)

    for _ in range(0, M):
        X, Y = (int(i) for i in input().split())
        X -= 1
        Y -= 1
        board[X][Y] = True
        xAttacked[X] = True
        yAttacked[Y] = True
        mainDiagAttacked[N - 1 + X - Y] = True
        offDiagAttacked[X + Y] = True

    forkedKnights = 0
    for x in range(0, N):
        for y in range(0, N):
            if board[x][y]:
                continue

            if (xAttacked[x] or yAttacked[y] or
                    mainDiagAttacked[N - 1 + x - y] or
                    offDiagAttacked[x + y]):
                continue

            attacking = 0
            offsets = [[[-2, 2], [-1, 1]], [[-1, 1], [-2, 2]]]
            for a, b in offsets:
                for i in a:
                    for j in b:
                        if is_X_Y_valid(board, x + i, y + j):
                            if board[x + i][y + j]:
                                attacking += 1

            if attacking >= 2:
                forkedKnights += 1

    print(forkedKnights)

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