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>

std::vector<char> t, d;
std::string s;
int N, Q;

int end(int);

int main()
{
	scanf("%d%d", &N, &Q);
	
	std::cin >> s;

	t.resize(Q);
	d.resize(Q);
	for (int i{}; i < Q; i++) scanf(" %c %c", &t[i], &d[i]);
	int left{-1}, right{N};
	while (left + 1 < right)
	{
		int mid{(left + right) / 2};
		if (end(mid) == -1) left = mid;
		else right = mid;
	}
	int sum{left + 1};
	left = -1; right = N;
	while (left + 1 < right)
	{
		int mid{(left + right) / 2};
		if (end(mid) == N) right = mid;
		else left = mid;
	}
	sum += N - right;
	printf("%d\n", N - sum);

	return 0;
}

int end(int pos)
{
	for (int i{}; i < Q; i++)
	{
		if (pos < 0 || pos >= N) return pos;
		if (t[i] != s[pos]) continue;
		if (d[i] == 'R') pos++;
		else pos--;
	}
	return pos;
}