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(i) for i in input().split())
S = input()
L = []
for i in range(Q):
    t, d = (i for i in input().split())
    L.append((t,d))

def func(k):
    now = k
    for t, d in L:
        if S[now] == t:
            if d == "R":
                now += 1
            else:
                now -= 1
        if now < 0:
            return "l"
        elif now >= N:
            return "r"
    if now < 0:
        return "l"
    elif now >= N:
        return "r"
    else:
        return None
ans = 0
left = 0
right = N
while True:
    if left >= right:
        break
    opt = (left + right)//2
    if func(opt) == "l":
        left = opt + 1
    else:
        right = opt
ans += right

left = 0
right = N
while True:
    if left >= right:
        break
    opt = (left + right)//2
    if func(opt) == "r":
        right = opt
    else:
        left = opt + 1
ans += (N - left)

print(N - ans)