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()
td=[list(map(str,input().split())) for i in range(q)]

def solve(ind):
    for tmp in td:
        if tmp[0] == s[ind]:
            if tmp[1]=="R":
                ind+=1
            else:
                ind-=1
            if ind < 0: # fall left
                return -1
            if len(s) <= ind : # fall right
                return 1
    return 0 # dont fall

l=0
r=len(s)
while r-l>1:
    mid=(l+r)//2

    if solve(mid)>=0:
        r=mid
    else:
        l=mid
ans=r

l=0
r=len(s)
while r-l>1:
    mid=(l+r)//2

    if solve(mid)<=0:
        l=mid
    else:
        r=mid
ans+=(len(s)-r)
print(n-ans)