p03458 AtCoder Beginner Contest 086 - Checker
AtCoDeer is thinking of painting an infinite two-dimensional grid in a checked pattern of side K. Here, a checked pattern of side K is a pattern where each square is painted black or white so that each connected component of each color is a K × K square. Below is an example of a checked pattern of side 3:

cba927b2484fad94fb5ff7473e9aadef.png

AtCoDeer has N desires. The i-th desire is represented by x_i, y_i and c_i. If c_i is `B`, it means that he wants to paint the square (x_i,y_i) black; if c_i is `W`, he wants to paint the square (x_i,y_i) white. At most how many desires can he satisfy at the same time?

Constraints

* 1 ≤ N ≤ 10^5
* 1 ≤ K ≤ 1000
* 0 ≤ x_i ≤ 10^9
* 0 ≤ y_i ≤ 10^9
* If i ≠ j, then (x_i,y_i) ≠ (x_j,y_j).
* c_i is `B` or `W`.
* N, K, x_i and y_i are integers.

Input

Input is given from Standard Input in the following format:


N K
x_1 y_1 c_1
x_2 y_2 c_2
:
x_N y_N c_N


Output

Print the maximum number of desires that can be satisfied at the same time.

Examples

Input

4 3
0 1 W
1 2 W
5 3 B
5 4 B


Output

4


Input

2 1000
0 0 B
0 1 W


Output

2


Input

6 2
1 2 B
2 1 W
2 2 B
1 0 B
0 6 W
4 5 W


Output

4
```python
class Acc2D:
    def __init__(self, a):
        h, w = len(a), len(a[0])
        self.acc2D = self._build(h, w, a)
        self.H = len(self.acc2D)
        self.W = len(self.acc2D[0])

    def _build(self, h, w, a):
        ret = [[0] * (w + 1) for _ in range(h + 1)]
        for r in range(h):
            for c in range(w):
                ret[r + 1][c + 1] = ret[r][c + 1] + ret[r + 1][c] - ret[r][c] + a[r][c]
                # 末項は必要に応じて改変すること
        return ret

    def get(self, r1, r2, c1, c2):
        # [r1,r2), [c1,c2) : 0-indexed
        if r1 < 0: r1 = 0
        if r2 >= self.H: r2 = self.H - 1
        if c1 < 0: c1 = 0
        if c2 >= self.W: c2 = self.W - 1
        acc2D = self.acc2D
        return acc2D[r2][c2] - acc2D[r1][c2] - acc2D[r2][c1] + acc2D[r1][c1]


def main():
    import sys
    input = sys.stdin.readline

    N, K = map(int, input().split())

    g = [[0] * (K * 2) for _ in range(K * 2)]
    for _ in range(N):
        x, y, c = input().split()
        x = int(x) % (K * 2)
        y = (int(y) - (K if c == 'B' else 0)) % (K * 2)
        g[x][y] += 1  # White

    acc2d = Acc2D(g)
    ans = -1
    for r in range(K):
        for c in range(K):
            t = acc2d.get(0, r, 0, c)
            t += acc2d.get(0, r, c + K, c + K * 2)
            t += acc2d.get(r, r + K, c, c + K)
            t += acc2d.get(r + K, r + K * 2, 0, c)
            t += acc2d.get(r + K, r + K * 2, c + K, c + K * 2)
            ans = max(ans, t, N - t)
    print(ans)


if __name__ == '__main__':
    main()

# import sys
# input = sys.stdin.readline
# 
# sys.setrecursionlimit(10 ** 7)
# 
# (int(x)-1 for x in input().split())
# rstrip()

```