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 <stdio.h>
int n, q;
char s[200005];
char t[200005];
char d[200005];
int lx, rx, ly, ry, e;
int check(int a) {
	for (int i = 0; i < q; i++) {
		if (s[a] == t[i]) {
			if (d[i] == 'L')a--;
			if (d[i] == 'R')a++;
		}
		if (a == -1)return -1;
		if (a == n)return n;
	}
	return a;
}
int main() {
	scanf("%d%d", &n, &q);
	scanf("%s", s);
	for (int i = 0; i < q; i++) {
		scanf(" %c %c", &t[i], &d[i]);
	}
	if (check(n - 1) == -1) {
		printf("0\n");
		return 0;
	}
	if (check(0) == n) {
		printf("0\n");
		return 0;
	}
	lx = -1;
	rx = n - 1;
	while (rx - lx > 1) {
		e = (rx + lx) / 2;
		if (check(e) == -1) {
			lx = e;
		}
		else {
			rx = e;
		}
	}
	ly = 0;
	ry = n;
	while (ry - ly > 1) {
		e = (ry + ly) / 2;
		if (check(e) == n) {
			ry = e;
		}
		else {
			ly = e;
		}
	}
	printf("%d\n", ly - rx + 1);
}
