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 getN():
    return int(input())

def getlist():
    return [int(x) for x in input().split()]

n, q = getlist()
sin = " " + input() + " "
oprs = []
lsafe = 1
rsafe = n
lborder = sin[:2]
rborder = sin[-2:]

for i in range(q):
    oprs.append(input().split())
for opr in oprs[::-1]:
    #print(lsafe, lborder, rsafe, rborder, opr)
    if opr[1] == "L":
        if opr[0] == lborder[1]:
            lsafe += 1
            lborder = lborder[1] + sin[lsafe]
        if opr[0] == rborder[1]:
            rsafe += 1
            rborder = rborder[1] + sin[rsafe+1]
    else: #opr = R
        if opr[0] == rborder[0]:
            rsafe -= 1
            rborder = sin[rsafe] + rborder[0]
        if opr[0] == lborder[0]:
            lsafe -= 1
            lborder = sin[lsafe-1] + lborder[0]

    if rsafe < lsafe:
        break
print(rsafe-lsafe+1)
