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 MAXN = 2e5 + 10;

int n, m, ansl, ansr, mid;
char s[MAXN];
struct node {
	char c, d;
} q[MAXN];

bool check(int pos)
{
	int x = mid;
	for (int i = 1; i <= m; i++) {
		if (s[x] == q[i].c) {
			q[i].d == 'L' ? --x : ++x;
			if (x < 1 || x > n)return x == pos;
		}
	}
	return false;
}

int main()
{
	ios::sync_with_stdio(false); cin.tie();
	cin >> n >> m >> s + 1;
	for (int i = 1; i <= m; i++)cin >> q[i].c >> q[i].d;
	int l = 1, r = n, ansl = 0;
	while (l <= r) {
		mid = (l + r) >> 1;
		check(0) ? (ansl = mid, l = mid + 1) : r = mid - 1;
	}
	l = 1, r = n, ansr = n + 1;
	while (l <= r) {
		mid = (l + r) >> 1;
		check(n + 1) ? (ansr = mid, r = mid - 1) : l = mid + 1;
	}
	cout << ansr - ansl - 1;
	return 0;
}