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 + 7;

int n, q;
char c[N];
char a[N], b[N];
int dl, dr;

int die(int x) {
	for (int i = 1; i <= q; i++) {
		if (a[i] != c[x])
			continue;
		if (b[i] == 'R')
			x++;
		else
			x--;
		if (x == 0)
			return -1;
		if (x == n + 1)
			return 1;
	}
	return 0;
}

int main() {
	cin >> n >> q;
	for (int i = 1; i <= n; i++)
		cin >> c[i];
	for (int i = 1; i <= q; i++)
		cin >> a[i] >> b[i];
	int l = 0, r = n + 1, md;
	while (r - l > 1) {
		md = (r + l) / 2;
		if (die(md) == -1)
			l = md;
		else
			r = md;
	}
	dl = l;
	l = 0, r = n + 1, md;
	while (r - l > 1) {
		md = (r + l) / 2;
		if (die(md) == 1)
			r = md;
		else
			l = md;
	}	
	dr = r;
	if (dr <= dl)
		dr = dl + 1;
	cout << n - dl - (n - (dr) + 1);
	return 0;
}



























