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
from functools import reduce

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


# めぐる式二分法
def bis(p, ok=-1, ng=10**18):
    mid = (ok + ng) // 2
    return (
        ok if abs(ok - ng) == 1 else
        bis(p, mid, ng) if p(mid) else
        bis(p, ok, mid)
    )


# Q回の呪文詠唱後、マスiにいたゴーレムが移動したマス。ただし、
# 0の場合、マス1から左に移動しようとして消滅したことを、
# N + 1の場合、マスNから右に移動しようとして消滅したことを表す。
def f(i):
    return reduce(
        lambda j, q: (
            0 if j == 0 else
            j - 1 if 1 <= j <= N and s[j - 1] == q[0] and q[1] == 'L' else
            j if 1 <= j <= N and s[j - 1] != q[0] else
            j + 1 if 1 <= j <= N and s[j - 1] == q[0] and q[1] == 'R' else
            N + 1
        ),
        zip(t, d),
        i
    )


# 二分法により、マス1から左に移動しようとして消滅したゴーレムの数と
# マスNから右に移動しようとして消滅したゴーレムの数の和を求める
ans = (
    bis(lambda i: f(i) == N + 1, ok=N + 1, ng=0) -
    bis(lambda i: f(i) == 0, ok=0, ng=N + 1) -
    1
)
print(ans)
