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;

pair<char, char> a[222222];
int main() {
	int n, q;
	string s;
	cin >> n >> q >> s;
	for (int i = 0; i < q; i++) {
		char t, d;
		scanf(" %c %c", &t, &d);
		a[i] = { t,d };
	}
	int l = 0, r = n + 1;
	while (l + 1 < r) {
		int m = (l + r) / 2, k = m;
		for (int i = 0; i < q; i++) {
			if (a[i].first == s[k - 1])
				a[i].second == 'L' ? k-- : k++;
			if (!k || k > n) break;
		}
		if (k) r = m;
		else l = m;
	}
	int x = l;
	l = 0, r = n + 1;
	while (l + 1 < r) {
		int m = (l + r) / 2, k = m;
		for (int i = 0; i < q; i++) {
			if (a[i].first == s[k - 1])
				a[i].second == 'L' ? k-- : k++;
			if (!k || k > n) break;
		}
		if (k > n) r = m;
		else l = m;
	}
	cout << r - x - 1 << endl;
	return 0;
}
