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
import sys
F = sys.stdin
N, Q = map(int, F.readline().strip("\n").split())
s = F.readline().strip("\n")
O = [None] * Q
for i in range(Q):
    O[i] = list(map(str, F.readline().strip("\n").split()))

leftlow, lefthigh = 0, N
while lefthigh - leftlow > 1:
    mid = (lefthigh + leftlow)//2
    now = mid
    for place, move in O:
        if place == s[now]:
            if move == "L": now -= 1
            else: now += 1
            if now == -1 or now == N: break
    if now == -1:leftlow = mid
    else: lefthigh = mid

rightlow, righthigh = 0, N
while righthigh - rightlow > 1:
    mid = (righthigh + rightlow)//2
    now = mid
    for place, move in O:
        if place == s[now]:
            if move == "L":now -= 1
            else: now += 1
            if now == -1 or now == N: break
    if now == N:righthigh = mid
    else: rightlow = mid

print(righthigh - lefthigh)