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 <cstdio>
#include <algorithm>

const int MN = 200005;
const int MM = 200005;

int N, M;
char s[MN];
char c1[MM][3], c2[MM][3];

int main() {
	scanf("%d%d", &N, &M);
	scanf("%s", s + 1);
	for (int i = 1; i <= M; ++i)
		scanf("%s%s", c1[i], c2[i]);
	int lb = 0, rb = 0;
	for (int i = M; i >= 1; --i) {
		if (*c2[i] == 'L') {
			if (s[lb + 1] == *c1[i]) ++lb;
			if (rb && s[N - rb + 1] == *c1[i]) --rb;
		}
		if (*c2[i] == 'R') {
			if (s[N - rb] == *c1[i]) ++rb;
			if (lb && s[lb] == *c1[i]) --lb;
		}
		if (lb + rb >= N) break;
	}
	printf("%d\n", std::max(N - lb - rb, 0));
	return 0;
}