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,M=map(int,input().split())
a = "a"+input()+"q"
k = []
for i in range(M):
  ta,tb=map(str,input().split())
  k.append([ta,tb])
k = k[::-1]
s = 1
t = N
c=0
for i, j in k:
  if j == "R" and i == a[t]:
    t-=1
    c+=1
  if j == "L" and i == a[s]:
    s+=1
  if j == "R" and i == a[s-1] and s> 1:
    s-=1
  if j == "L" and i == a[t+1] and t< N:
    t+=1
  if s==t+1 and N!=0:break
if N>1:print(t-s+1)
else: 
  if s+c+1>1:print(1)
  else:print(0)
