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()
t,d = [],[]
for i in range(q):
    tt,dd = input().split()
    t.append(tt)
    d.append(dd)

def judge(k):#0:false 1:L 2:R
    pos = k
    posc = s[k]

    for i in range(q):
        if(t[i] != posc):continue
        if(d[i] == 'L'):
            pos -= 1
        else:
            pos += 1
        if pos == -1:
            return 1
        if pos == n:
            return 2
        posc = s[pos]

if(judge(0) != 1):ansl = 0
else:
    ll,rr = 0,n
    for i in range(100):
        if(rr -ll == 1): break
        
        md = (ll+rr) // 2

        if(judge(md) != 1) : rr = md
        else : ll = md
    ansl = ll+1

if(judge(n-1) != 2):ansr = 0
else:
    ll,rr = -1,n-1
    for i in range(100):
        if(rr -ll == 1): break
        
        md = (ll+rr) // 2

        if(judge(md) != 2) : ll = md
        else : rr = md
    ansr = n-rr

print(n-ansl-ansr)