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 = []
lend = 0
rend = N-1

for i in range(Q):
    t,d = map(str,input().split())
    td.append([t,d])
td = td[::-1]
for i,j in td:
    if j == "L" and i == s[lend]:#左端を1つずらす
        lend += 1
    if j == "R" and i == s[rend]:#右端を1つずらす
        rend -= 1  
    if rend < (N-1) and j == "L" and i == s[rend+1]:#1つ前の位置を参照して右に戻す
        rend += 1
    if lend > 0 and j == "R" and i == s[lend-1]:#1つ前の位置を参照して左に戻す
        lend -= 1
    if lend > rend:
        break

print(rend - lend + 1)