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() + '  '

ts,ds = [None]*Q, [None]*Q
for i in range(Q):
    ts[i], ds[i] = input().split()

def getFinalPos(pos):
    for t, d in zip(ts, ds):
        if s[pos]==t:
            if d=='L':
                pos -= 1
            else:
                pos += 1
    return pos


def b_search(l, nr, t):
    if abs(nr - l) <= 1:
        return l
    mid = (nr + l) // 2
    if getFinalPos(mid) == t:
        return b_search(mid, nr, t)
    else:
        return b_search(l, mid, t)

l = b_search(0, N+2, 0)
nr = b_search(N+1, 0, N+1)

print(nr - 1 - l)
