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
sys.setrecursionlimit(10**9)
n,q=map(int,input().split())
s=[None]+list(input())+[None]
L=[tuple(input().split()) for _ in range(q)]

def judge(k):
    now=k
    if now==0:
        return 1
    if now==n+1:
        return 2
    for t,d in L:
        if s[now]==t:
            if d=='R':
                now+=1
            else:
                now-=1
        if now==0:
            return 1
        elif now==n+1:
            return 2
    else:
        return 0

left,right=0,n+1
while right-left>1:
    mid=(left+right)//2
    if judge(mid)==1:
        left=mid
    else:
        right=mid
out=left
left,right=0,n+1
while right-left>1:
    mid=(left+right)//2
    if judge(mid)==2:
        right=mid
    else:
        left=mid
out+=(n+1-right)
print(n-out)