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()
td = [input().split() for i in range(q)]
s = "s" + s + "e"

def can_go(i, left=True):
    end = 0 if left else n+1
    if i == end:
        return True
    start = i
    for t, d in td:
        if start == end:
            return True
        if t == s[start]:
            if d == "L":
                start -= 1
            else:
                start += 1
    return start == end

ans = []

left = 0
right = n+1
while right - left > 1:
    center = (left+right)//2
    if can_go(center):
        left = center
    else:
        right = center
ans.append(left)

left = 0
right = n+1
while right - left > 1:
    center = (left+right)//2
    if can_go(center, left=False):
        right = center
    else:
        left = center
ans.append(right)

#print(ans)
print(max(0, ans[1]-ans[0]-1))