There are N squares numbered 1 to N from left to right. Each square has a character written on it, and Square i has a letter s_i. Besides, there is initially one golem on each square.

Snuke cast Q spells to move the golems.

The i-th spell consisted of two characters t_i and d_i, where d_i is `L` or `R`. When Snuke cast this spell, for each square with the character t_i, all golems on that square moved to the square adjacent to the left if d_i is `L`, and moved to the square adjacent to the right if d_i is `R`.

However, when a golem tried to move left from Square 1 or move right from Square N, it disappeared.

Find the number of golems remaining after Snuke cast the Q spells.

Constraints

* 1 \leq N,Q \leq 2 \times 10^{5}
* |s| = N
* s_i and t_i are uppercase English letters.
* d_i is `L` or `R`.

Input

Input is given from Standard Input in the following format:


N Q
s
t_1 d_1
\vdots
t_{Q} d_Q


Output

Print the answer.

Examples

Input

3 4
ABC
A L
B L
B R
A R


Output

2


Input

8 3
AABCBDBA
A L
B R
A R


Output

5


Input

10 15
SNCZWRCEWB
B R
R R
E R
W R
Z L
S R
Q L
W L
B R
C L
A L
N L
E R
Z L
S L


Output

3
import sys

def main():
    input = sys.stdin.readline
    N, Q = map(int, input().split())
    S = list(map(str, input().strip()))
    order = [tuple(map(str, input().split())) for _ in range(Q)]
    order = order[::-1]

    left, right = 0, N-1
    for a in order:
        t, d = a[0], a[1]

        if d == 'L':
            if S[left] == t:
                left += 1
                if left > N - 1:
                    return 0

            if right < N - 1 and S[right + 1] == t:
                right = min(N - 1, right + 1)

        else:
            if left > 0 and S[left - 1] == t:
                left = max(0, left - 1)

            if S[right] == t:
                right -= 1
                if right < 0:
                    return 0

    return right - left + 1


if __name__ == '__main__':
    print(main())
