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=[input().split() for _ in [0]*Q]
def ith_move(i):
    k=i
    for t,d in TD:
        if S[k]==t:
            k+=1 if d=='R' else -1
        if k==-1 or k==N:return k
    return k
#print([(i,ith_move(i)) for i in range(N)])

low=0; high=N; L=(high+low)//2 #左に落ちる一番右を探索
while low<=high:
    fall = ith_move(L)==-1
    #print(f"L [{low}, {high}); {L}:{fall}")
    if low==high: L = high if fall else high-1; break
    if fall: low = L+1
    else: high = L-1
    L = (high+low)//2

low=0; high=N; R=(high+low)//2 #右に落ちない一番右を探索
while low<=high:
    fall = ith_move(R)==N
    #print(f"R [{low}, {high}); {R}:{fall}")
    if low==high: R = high-1 if fall else high; break
    if fall: high = R-1
    else: low = R+1
    R = (high+low)//2

#print(L,R)
print(R-L)