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 <bits/stdc++.h>

using namespace std;

int n, m;

char ch[200010];

int A[200010], B[200010];

int Do(int x) {
	for(int i = 1; i <= m; i++)
		if(ch[x] == A[i]) {
			x += B[i];
			if(x == 0 || x == n + 1) return x;
	}
	return x;
}

int main() {
scanf("%d%d", &n, &m);
	scanf("%s", ch + 1);
	for(int i = 1; i <= m; i++) {
		char X[3], Y[3];
		scanf("%s%s", X, Y);
		A[i] = X[0], B[i] = Y[0] == 'R' ? 1 : -1;
	}
	int ansL = 0;
	for(int l = 1, r = n; l <= r; ) {
		int md = (l + r) / 2;
		if(Do(md) == 0) ansL = md, l = md + 1; else r = md - 1;
	}
	int ansR = n + 1;
	for(int l = 1, r = n; l <= r; ) {
		int md = (l + r) / 2;
		if(Do(md) != n + 1) l = md + 1; else ansR = md, r = md - 1;
	}
	printf("%d\n", ansR - ansL - 1);
	return 0;
}