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>

#define ft first
#define sd second

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<char, char> pcc;

const int MAXN = 200 * 1000 + 23;





bool check(int);
void inp();
void gedit();

int n, q, ans;
string s;
char save = 'L';
pcc c[MAXN];

int main() {
	inp();
	gedit();
	save = 'R';
	reverse(s.begin(), s.end());
	gedit();
	cout << n - ans;
	return 0;
}
void inp() {
	cin >> n >> q >> s;
	for (int i = 0; i < q; i++)
		cin >> c[i].ft >> c[i].sd;
}
bool check(int v) {
	for (int i = 0; i < q; i++) {
		if (c[i].ft == s[v])
			v = v + ((c[i].sd == save)? -1: 1);
		if (v < 0)
			return true;
	}
	return false;
}
void gedit() {
	int up = n + 1, dw = -1;
	while (up - dw > 1) {
		int m = ((up + dw) >> 1);
		if (check(m))
			dw = m;
		else
			up = m;
	}
	ans += up;
}