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 _ in [0]*Q]

def f(n):
    s = S[n]
    for t,d in TD:
        if s==t:
            if d=="L":
                n -= 1
            else:
                n += 1
            if n<0 or N<=n: break
            s = S[n]
    return n

def binary_search(l,r,func):
    if func(l):return l-1
    if not func(r):return r
    while l+1<r:
        i = (l+r)//2
        if func(i):
            r = i
        else:
            l = i
    return l

l = binary_search(0,N-1,lambda n:f(n)>=0)
r = binary_search(0,N-1,lambda n:f(n)>=N)
print(r-l)