Forest density

import sys


def main():
    data = sys.stdin.buffer.read().split()
    it = iter(data)
    n = int(next(it))
    q = int(next(it))
    forest = [
        list(map(lambda c: 0 if c == "." else 1, list((str(next(it))).split("'")[1])))
        for _ in range(n)
    ]

    premade = []
    for i in range(n):
        premade.append([])
        for j in range(n):
            val = forest[i][j]
            if i > 0 and j > 0:
                val += premade[i][j - 1] + premade[i - 1][j] - premade[i - 1][j - 1]
            premade[i].append(val)

    for _ in range(q):
        a = int(next(it)) - 1
        b = int(next(it)) - 1
        c = int(next(it)) - 1
        d = int(next(it)) - 1

        val = premade[c][d]
        if a > 0 and b > 0:
            val += premade[a - 1][b - 1] - premade[c][b - 1] - premade[a - 1][d]
        print(val)


main()

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER