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;

const int N = 2e5 + 100;

int n, q;
char t[N], d[N];
string s;

int get(int dex) {
	for (int i = 0; i < q; i++)
		if(t[i] == s[dex]) {
			if(d[i] == 'L')
				dex--;
			else
				dex++;
			if(dex < 0)
				return -1;
			if(dex >= n)
				return 1;
		}
	return 0;
}

int get_l() {
	int l = -1, r = n;
	while(r - l > 1) {
		int c = (l + r) >> 1;
		if(get(c) == -1)
			l = c;
		else
			r = c;
	}
	return l;
}

int get_r() {
	int l = -1, r = n;
	while(r - l > 1) {
		int c = (l + r) >> 1;
		if(get(c) == 1)
			r = c;
		else
			l = c;
	}
	return r;
}

int main() {
	ios::sync_with_stdio(false), cin.tie(0);
	cin >> n >> q >> s;
	for (int i = 0; i < q; i++)
		cin >> t[i] >> d[i];
	cout << n - (get_l() + 1 + n - get_r());
	return 0;
}