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()
            
Q = []
for _ in range(q):
    Q.append(input().split())

s    = '$'+s+'$' 
         
def isRemove(pos, s, Q, target):
    cur  = pos        
            
    for t, d in Q:
        if cur == target:
            break
        
        if s[cur] != t:
            continue
            
        if d == 'L':
            cur -= 1
        else:
            cur += 1
            
    if cur == target:
        return True
    return False
          
l = 0
r = len(s) - 1
            
while r - l > 1:
    md = (r+l) // 2
    if isRemove(md, s, Q, 0):
        l = md
    else:
        r = md
            
mostRight = l
            
l = 0
r = len(s) - 1
            
while r - l > 1:
    md = (r+l) // 2
    if isRemove(md, s, Q, len(s)-1):
        r = md
    else:
        l = md        
            
mostLeft = r

print(mostLeft-mostRight-1) #AABCBDBA