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 <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>
#include <deque>

using namespace std;

int main() {
	int n, q;
	string s;
	cin >> n >> q >> s;

	vector<char> t(q), d(q);
	for (int i = 0; i < q; i++) {
		cin >> t[i] >> d[i];
	}

	s = string("?") + s + string("?");
	int idx_l = 1;
	int idx_r = n;

	for (int i = q - 1; i >= 0; i--) {
		char c = t[i];
		if (d[i] == 'L') {
			if (s[idx_l] == c) {
				idx_l++;
			}
			if (s[idx_r + 1] == c) {
				idx_r++;
			}
		} else {
			if (s[idx_r] == c) {
				idx_r--;
			}
			if (s[idx_l - 1] == c) {
				idx_l--;
			}
		}

		if (idx_l > idx_r) {
			break;
		}
	}

	int ans = idx_r - idx_l + 1;
	cout << ans << endl;

	return 0;
}
