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;

char t[1 << 18], d[1 << 18];
int n, q; string s;

int sta(int x) {
	for(int i = 0; i < q; i++) {
		if (s[x] == t[i]) {
			if (d[i] == 'L')x--;
			else x++;
		}
		if (x < 0)return 1;
		else if (x >= n)return 2;
	}
	return 0;
}
void solve() {
	cin >> n >> q >> s;
	for(int i = 0; i < q; i++) {
		cin >> t[i] >> d[i];
	}
	int le = 0, ri = n;
	while (ri - le > 1) {
		int mid = (le + ri) / 2;
		if (sta(mid) == 1)le = mid;
		else ri = mid;
	}
	int cle = 0, cri = n;
	while (cri - cle > 1) {
		int mid = (cle + cri) / 2;
		if (sta(mid) == 2)cri = mid;
		else cle = mid;
	}
	int ans = cle - ri + 1;
	if (ans < 0)ans = 0;
	cout << ans << endl;
}
int main() {
	solve();
}
