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 <string>
#include <algorithm>

#define MAX (int)2e5
	
//にぶたんver  未完成

using namespace std;
typedef pair<char,int> P;

int n, q;
string s;
P spels[MAX+1];

int journey(int k) {
	for (int i=0; i<q; i++) {
		if (s[(size_t)k] != spels[i].first) continue;
		k += spels[i].second;
		if (k == n) return 1;
		else if (k == -1) return -1;
	}
	return 0;
}

int main() {
	cin >> n >> q >> s;
	for (int i=0; i<q; i++) {
		char t, d;
		cin >> t >> d;
		spels[i] = P(t, d == 'R' ? 1 : -1);
	}

	int a1 = 0, a2 = 0, b1 = n-1, b2 = n-1, j1, j2;
	while (true) {
		j1 = journey((a1 + b1)/2);
		j2 = journey((a2 + b2 + 1)/2);
		if (b1 - a1 <= 1 && b2 - a2 <= 1) break;
		if (j1 == -1) a1 = (a1 + b1)/2;
		else b1 = (a1 + b1)/2;
		if (j2 == 1) b2 = (a2 + b2 + 1)/2;
		else a2 = (a2 + b2 + 1)/2;
	}
	cout << b2 - a1 + (int)(j1==0) + (int)(j2==0) - 1 << '\n';
	return 0;
}