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
N, Q = list(map(int, input().split()))
s = input()
spells =  [input().split() for i in range(Q)]

def sim(pos, s, spells, N):
    for sp in spells:
        if s[pos] == sp[0]:
            pos += -1 if sp[1] == "L" else 1
            if pos < 0:
                return "LDead"
            if pos >= N:
                return "RDead"
    return "Alive"

#LD探し
Lpos = -1
Rpos = N
while Lpos+1<Rpos:
    pos = (Lpos+Rpos)//2
    if sim(pos, s, spells, N) == "LDead":
        Lpos = pos
    else:
        Rpos = pos
LDpos = Lpos ###LDeadの中で一番境界に近いもの

#RD探し
Lpos = -1
Rpos = N
while Lpos+1<Rpos:
    pos = (Lpos+Rpos)//2
    if sim(pos, s, spells, N) == "RDead":
        Rpos = pos
    else:
        Lpos = pos
RDpos = Rpos ###RDeadの中で一番境界に近いもの

print(max(0,RDpos-LDpos-1))