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
def sim(i):
    for t, d in qs:
        if S[i] == t:
            div = 1 if d == "R" else -1
            i += div
            if i == 0:
                return 0
            elif i == N+1:
                return N+1
    return i

def bin_search_left():
    ok = 0
    ng = N+1

    while abs(ok-ng)>1:
        mid = (ok+ng) //2
        res = sim(mid)
        #print(ok,ng,mid,res)
        if res == 0:
            ok = mid
        if res >0:
            ng = mid
    return ok


def bin_search_right():
    ng = 0
    ok = N+1

    while abs(ok-ng)>1:
        mid = (ok+ng) //2
        res = sim(mid)
        #print(ok,ng,mid,res)
        if res < N+1:
            ng = mid
        if res >= N+1:
            ok = mid
    return ok


N, Q = map(int,input().split())
S = "0"+input()+"0"
qs = []
for _ in range(Q):
    t, d = input().split()
    qs.append((t,d))

L = bin_search_left()
R = bin_search_right()
print(N-L-(N+1-R))