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 bisect(f, ok, err):
    while abs(ok - err) > 1:
        m = (ok + err) // 2
        if f(m):
            ok = m
        else:
            err = m
    return ok

def c2i(c): return ord(c)-ord("A")
def mapst(s,t): return c2i(s),-1 if t=="L" else 1
def main():
    N,Q=map(int, input().split())
    S=list(map(c2i, input()))
    TD=[mapst(*input().split())for _ in range(Q)]
    def f(m):
        for t,d in TD:
            m+=(S[m]==t)*d
            if m<0 or m>=N: return False
        return True
    l=bisect(f, N, -1)
    def f(m):
        for t,d in TD:
            m+=(S[m]==t)*d
            if m<0 or m>=N: return False
        return True
    r=bisect(f, -1, N)
    print(r-l+1 if l<=r else 0)

if __name__ == "__main__":
    main()