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)]


def check(i):
    """どっちに落ちるかを返す
    -1,0,1

    Args:
        i ([type]): [description]
    """

    if i == -1:
        return -1
    if i == N:
        return 1

    for q in range(Q):
        t, d = TD[q]
        if t == s[i]:
            if d == "L":
                i -= 1
            else:
                i += 1

            if i == -1:
                return -1
            if i == N:
                return 1
    return 0


s_index = -1  # include
e_index = N  # include
while s_index+1 < e_index:
    c_index = (s_index+e_index)//2
    if check(c_index) == -1:
        s_index = c_index
    else:
        e_index = c_index
left = s_index

s_index = -1  # include
e_index = N  # include
while s_index+1 < e_index:
    c_index = (s_index+e_index)//2
    if check(c_index) == 1:
        e_index = c_index
    else:
        s_index = c_index
right = e_index


print(right-left-1)
