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;

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

bool check1(int m) {
	for (int i = 0; i < q; i++) {
		if (s[m] == t[i]) {
			if (d[i] == 'R')
				m++;
			else
				m--;
			if (m == n)
				return true;
		}
	}
	return false;
}

bool check2(int m) {
	for (int i = 0; i < q; i++) {
		if (s[m] == t[i]) {
			if (d[i] == 'R')
				m++;
			else
				m--;
			if (m < 0)
				return true;
		}
	}
	return false;
}

int main() {
	ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> q >> s;
	for (int i = 0; i < q; i++)
		cin >> t[i] >> d[i];
	int s = -1, e = n;
	while (e - s > 1) {
		int m = (s + e) / 2;
		if (check1(m))
			e = m;
		else
			s = m;
	}
	ans = e - 1;
	s = 0, e = n + 1;
	while (e - s > 1) {
		int m = (s + e) / 2;
		if (check2(m))
			s = m;
		else
			e = m;	
	}
	ans -= s;
	return cout << (ans >= 0 ? ans : 0), 0;
}