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,heapq
from collections import deque,defaultdict
printn = lambda x: sys.stdout.write(x)
inn = lambda : int(input())
inl   = lambda: list(map(int, input().split()))
inm   = lambda:      map(int, input().split())
DBG = True  and False
def ddprint(x):
  if DBG:
    print(x)

n,q = inm()
s = input()
ddprint("n {} q {} s {}".format(n,q,s))
t = []
d = []
for i in range(q):
    tt,dd = input().split()
    t.append(tt)
    d.append(dd)
l = -1
r = n
for i in range(q-1,-1,-1):
    ddprint("i {} l {} r {}".format(i,l,r))
    if l < n-1 and t[i] == s[l+1] and d[i] == 'L':
        l += 1
    if l >= 0 and t[i] == s[l] and d[i] == 'R':
        l -= 1
    if r > 0 and t[i] == s[r-1] and d[i] == 'R':
        r -= 1
    if r < n and t[i] == s[r] and d[i] == 'L':
        r += 1
print(r-l-1)
