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
input = sys.stdin.readline

N,Q = tuple(map(int,input().split()))

s = input()

Query = []
for i in range(Q):
    Query.append(input().split())
#A L
#B L
#B R
#A R



left,right = 0,N-1

## 最終的に生き残っているのをleftとrightにする
## 

for ch,way in reversed(Query):
    #print(left,right,ch,way,s[left],s[right])
    if way == "L":
        if ch == s[left]:
            left += 1
        if right < N-1 and ch == s[right+1]:
            right = min(right + 1,N-1)
        #print("L",left,right,ch,way,s[left],s[right])
    else:
        if left > 0 and ch == s[left-1] :
            left = max(left -1,0)
        if ch == s[right]:
            right -= 1
        #print("R",left,right,ch,way,s[left],s[right])
print(max(0,right-left+1))