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() + "#"
l = [tuple(input().split()) for _ in range(q)]
def move(x,g):
  for i in l:
    if i[0] == s[x]:
      x += (i[1]=="R") or -1
  return x==g
hi1 = n+1
lo1,lo2 = 0,0
while hi1-lo1>1:
  mid1 = (hi1+lo1)//2
  if move(mid1,n+1):
    hi1 = mid1
  else:
    lo1 = mid1
hi2 = hi1
while hi2-lo2>1:
  mid2 = (hi2+lo2)//2
  if move(mid2,0):
    lo2 = mid2
  else:
    hi2 = mid2
print(hi1-lo2-1)