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 = [int(x) for x in input().split()]
S = input()
TD = []
for _ in range(Q):
    t, d = input().split()
    TD.append((t, d))


def isDead(targetIdx):
    ti = targetIdx
    for t, d in TD:
        if t == S[ti]:
            if d == 'L':
                ti -= 1
                if ti == -1:
                    return -1
            else:
                ti += 1
                if ti == N:
                    return +1
    return 0


l, r = -1, N

while r - l > 1:
    t = (l + r) // 2
    if isDead(t) == -1:
        l = t
    else:
        r = t

L = r

l, r = -1, N

while r - l > 1:
    t = (l + r) // 2
    if isDead(t) == +1:
        r = t
    else:
        l = t

R = l

print(R - L + 1)

# print((L, R))
# print([isDead(t) for t in range(N)])
