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;
typedef long long ll;

const int maxn(2e5 + 5);

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

inline int check(int x) {
	int i;
	for (i = 1; i <= q && x && x <= n; ++i) if (t[i] == s[x]) d[i] == 'L' ? --x : ++x;
	return x;
}

int main() {
	scanf("%d%d %s", &n, &q, s + 1);
	int i, l, r, mid, ret1 = 0, ret2 = n + 1;
	for (i = 1; i <= q; ++i) scanf(" %c %c", &t[i], &d[i]);
	l = 1, r = n;
	while (l <= r) {
		mid = (l + r) >> 1;
		if (check(mid) < 1) ret1 = mid, l = mid + 1;
		else r = mid - 1;
	}
	l = 1, r = n;
	while (l <= r) {
		mid = (l + r) >> 1;
		if (check(mid) > n) ret2 = mid, r = mid - 1;
		else l = mid + 1;
	}
	printf("%d\n", n - min(n, ret1 + n - ret2 + 1));
    return 0;
}