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
# -*- coding: utf-8 -*-
def vanish_golem(pos, n, s, spells):
    for t, d in spells:
        if pos < 0:
            return -1
        if pos >= n:
            return 1

        if s[pos] == t:
            pos += 1 if d == 'R' else -1

    if pos < 0:
        return -1
    elif pos >= n:
        return 1
    else:
        return 0


def search_vanish_golem(n, s, spells, th):
    l = 0
    h = n-1

    while l <= h:
        t = l + (h - l) // 2
        v = vanish_golem(t, n, s, spells)
        if v < th:
            l = t + 1
        else:
            h = t - 1

    return l


n, q = map(int, input().split())
s = input()

td = [input().split() for _ in range(q)]

l_cnt = search_vanish_golem(n, s, td, 0)
r_cnt = n - search_vanish_golem(n, s, td, 1)

print(n - l_cnt - r_cnt)
