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 = map(int, input().split())
s = input()
t, d = zip(*(input().split() for _ in range(Q)))


def f(i):
    i -= 1
    if i < 0:
        return -1
    if i >= N:
        return 1
    for j in range(Q):
        if s[i] == t[j]:
            i += 1 if d[j] == 'R' else -1
        if i < 0:
            return -1
        elif i >= N:
            return 1
    return 0


h, l = N + 1, 1
while h > l:
    i = (h + l) // 2
    r = f(i)
    if r == 1:
        h = i
    else:
        l = i + 1

ans = N - h + 1

h, l = N, 0
while h > l:
    i = (h + l + 1) // 2
    r = f(i)
    if r == -1:
        l = i
    else:
        h = i - 1

ans = N - ans - l

print(ans)
