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=list(input())
S=[0]+S+[N+1]
TD=[list(input().split()) for _ in range(Q)]

def solve(place):
    if place == 0:
        return ('Left')
    elif place == N+1:
        return ('Right')
    for td in TD:
        char,to=td
        if S[place]!=char:continue

        if to=='L':place-=1
        elif to=='R':place+=1

        if place==0:
            return('Left')
        elif place==N+1:
            return('Right')
    return('Not Drop')

l,r=0,N+1
L,R=0,N+1

while abs(r-l)>1:
    m=(l+r)//2
    if solve(m)=='Left':
        L=m
        l,r=m,r
    else:
        l,r=l,m

l,r=0,N+1

while abs(r-l)>1:
    m=(l+r)//2
    if solve(m)=='Right':
        R=m
        l,r=l,m
    else:
        l,r=m,r

print(max(R-L-1,0))
