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 collections import Counter

n, q = map(int, input().split())
s = list(input())
td = [list(input().split()) for _ in range(q)]

if n == 1:
    for t, d in td:
        if s[0] == t:
            print(0)
            exit()
    print(1)
    exit()

def vanish(x):
    for t, d in td:
        if s[x] == t:
            if d == 'L':
                x -= 1
                if x == -1:
                    return -1
            else:
                x += 1
                if x == n:
                    return n
    return x

L = 0
R = n
U = 0
ans = n

while R - L > 1:
    M = (L + R) // 2
    ret = vanish(M)
    if ret == -1:
        L = M
    else:
        R = M

ret = vanish(L)
if ret == -1:
    ans -= L + 1
else:
    ans -= L

L = 0
R = n

while R - L > 1:
    M = (L + R) // 2
    ret = vanish(M)
    if ret == n:
        R = M
    else:
        L = M

ret = vanish(L)
if ret == n:
    ans -= n - L
else:
    ans -= n - 1 - L

print(ans)


