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())
sl = list(input())

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

def simulate(i):
    if i < 0:
        return 0
    if i > n - 1:
        return 2
    now = sl[i]
    for t, d in tdl:
        if t == now:
            if d == "R":
                i += 1
            else:
                i -= 1
        if i == -1:
            return 0
        if i == n:
            return 2
        now = sl[i]
    return 1
ub = n+1
lb = -2
while True:
    if ub == lb:
        ans = ub
        break
    target = (ub + lb) // 2 + 1
    if simulate(target) == 0:
        lb = target
    else:
        ub = target - 1

ub = n+1
lb = -2
while True:
    if ub == lb:
        ans2 = ub
        break
    target = (ub + lb) // 2
    if simulate(target) == 2:
        ub = target
    else:
        lb = target + 1


print(n-(ans+1+n-ans2))

