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
#include<iostream>
#include<queue>
#include<bitset>
using namespace std; // 575

const int MAX = 200002;
int main() {
	int N, Q;
	static char t[MAX], d[MAX];
	string s;
	cin >> N >> Q >> s;
	for (int i = 0;i < Q;++ i) cin >> t[i] >> d[i];
	
	int l = -1, r = N;
	for (int i = Q - 1;i >= 0;-- i) {
		if (s[l + 1] == t[i] && d[i] == 'L') ++ l;
		if (0 <= l && s[l] == t[i] && d[i] == 'R') -- l;
		if (s[r - 1] == t[i] && d[i] == 'R') -- r;
		if (r < N && s[r] == t[i] && d[i] == 'L') ++ r;
		if (r - l <= 1) break;
	}
	cout << max(0, r - l - 1);
	return 0;
}
/*
31536000のコメント解説欄
ここテンプレで用意してるから、A問題とかだとこの先空欄の危険あり
また、コンテスト後に https://31536000.hatenablog.com/ で解説していると思うので、良かったら読んでねー

逆順に考えれば良い
そうすれば左右から順に伸ばしていくだけになる
最後に、残った区間はその間なので一発で求まる
*/