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
# -*- coding: utf-8 -*-
"""
Created on Sat Mar 30 21:21:19 2019

@author: Yamazaki Kenichi
"""

N,Q = map(int,input().split())
s = input()
A = [list(input().split()) for i in range(Q)]

def a(b,i):
    if i == -1 or i == N:
        return i        
    if b[0] == s[i]:
        return i - 1 if b[1] == 'L' else i + 1
    else:
        return i
def ar(i):
    for j in range(Q):
        if i == N:
            return False
        i = a(A[j],i)
    return False if i == N else True
def al(i):
    for j in range(Q):
        if i == -1:
            return False
        i = a(A[j],i)
    return False if i == -1 else True
def bir(i,j):
    if i + 1 == j:
        return i
    if ar((i+j)//2):
        return bir((i+j)//2,j)
    else:
        return bir(i,(i+j)//2)
def bil(i,j):
    if i + 1 == j:
        return i
    if al((i+j)//2):
        return bil(i,(i+j)//2)
    else:
        return bil((i+j)//2,j)
ans = bir(0,N) - bil(0,N)
print(ans)
