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
import sys

N,Q=map(int,input().split())
s=[-1]
s+=list(map(lambda e:ord(e)-65,list(input())))
s+=[-1]
t=[]
d=[]
for i in range(Q):
    ti,di=sys.stdin.readline().rstrip().split()
    ti=ord(ti)-65
    di = -1 if di=='L' else +1
    t.append(ti)
    d.append(di)

def solve(n):
    for i in range(Q):
        if s[n]==t[i]:
            n+=d[i]
    return n

def find_match(x):
    f1 = 1
    f2 = N + 1
    while f1 != f2:
        f3 = (f1 + f2) // 2
        if solve(f3) == x:
            f1 = f3 + 1
        else:
            f2 = f3
    return f1

def find_notmatch(x):
    f1 = 1
    f2 = N + 1
    while f1 != f2:
        f3 = (f1 + f2) // 2
        #print(f1,f2,f3,solve(f3),x)
        if solve(f3) != x:
            f1 = f3 + 1
        else:
            f2 = f3
    return f1

#for i in range(1,N+1):
#    print(solve(i))

print(find_notmatch(N+1)-find_match(0))
