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()

X = []
for i in range(Q):
    t, d = input().split()
    if d == 'L':
        X.append([t, -1])
    else:
        X.append([t, 1])
        
def check(m):
    i = m
    for x in X:
        if x[0] == s[i]:
            i += x[1]
            if i < 0:
                return -1
            if i >= N:
                return 1
    return 0

L, R = -1, N
while R - L > 1:
    M = (L + R) // 2
    if check(M) < 0:
        L = M
    else:
        R = M  
A = L

L, R = -1, N
while R - L > 1:
    M = (L + R) // 2
    if check(M) > 0:
        R = M
    else:
        L = M
B = R

print(B - A - 1)