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
def binsearch(l, r, fn):
    while r - l > 1:
        m = (l + r) // 2
        if fn(m):
            l = m
        else:
            r = m
    return l

def main():
    N, Q = map(int, input().split())
    s = input()
    TD = [input().split() for _ in range(Q)]
    def die(n):
        if n < 0:
            return -1
        if n >= N:
            return 1
        for t, d in TD:
            if s[n] != t:
                continue
            if d == 'L':
                n -= 1
                if n < 0:
                    return -1
            else:
                n += 1
                if n >= N:
                    return 1
        return 0
    L = binsearch(-1, N, lambda x: die(x) == -1)
    R = binsearch(-1, N, lambda x: die(x) != 1)
    return R - L

print(main())
