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 unsigned int ui;
typedef long long ll;
typedef unsigned long long ull;

constexpr int MAXN = 200000, MAXQ = 200000;

char s[MAXN + 2];
char q[MAXQ + 2][2];
int N, Q;

int sim(int p) {
	if(!(p >= 0 && p < N))
		return p;
	for(int i = 0; i < Q; i++) {
		if(q[i][0] == s[p]) {
			if(q[i][1] == 'L') {
				if(--p < 0)
					return p;
			} else {
				if(++p >= N)
					return p;
			}
		}
	}
	return p;
}

int main() {
	cin >> N >> Q >> s;
	for(int i = 0; i < Q; i++)
		cin >> q[i][0] >> q[i][1];
	int l = -1, r = N - 1;
	do {
		int m = (l + r) / 2;
		if(sim(m) == -1)
			l = m + 1;
		else
			r = m - 1;
	} while(l <= r);
	int ans = l;
	l = 0, r = N;
	do { 
		int m = (l + r) / 2;
		if(sim(m) == N)
			r = m - 1;
		else
			l = m + 1;
	} while(l <= r);
	ans += N - l;
	ans = N - ans;
	cout << ans << endl;
}
