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 = [int(i) for i in input().split(" ")]
s = input()
qs = [[]] * q

for i in range(0, q):
    qs[i] = input().split(" ")

def dest(i):
    global s
    global n
    global qs
    cur = i
    for qsi in qs:
        if s[cur] == qsi[0]:
            if qsi[1] == "R":
                cur += 1
                if cur >= n:
                    return cur
            else:
                cur -= 1
                if cur < 0:
                    return cur
    return cur

def sL(l, r):
    if l == r:
        return l
    h = (l + r) // 2
    if dest(h) < 0:
        return sL(h + 1, r)
    else:
        return sL(l, h)
    
def sR(l, r):
    global n
    if l == r:
        return l
    h = (l + r) // 2
    if dest(h) < n:
        return sR(h + 1, r)
    else:
        return sR(l, h)
    
print(sR(0, n) - sL(0, n))