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;

int N, Q;
char s[200002], t[200000], d[200000];

int judge(int x){
	if(x == 0) return -1;
	if(x == N+1) return 1;
	for(int i=0; i<Q; i++){
		if(s[x] == t[i]){
			if(d[i] == 'L') x--;
			else x++;
			if(x <= 0) return -1;
			if(x > N) return 1;
		}
	}
	return 0;
}

int search_left(void){
	int i = 0, j = N+1;
	while(j-i > 1){
		int m = (i+j)/2;
		if(judge(m) >= 0) j = m;
		else i = m;
	}
	return j;
}

int search_right(void){
	int i = 0, j = N+1;
	while(j-i > 1){
		int m = (i+j)/2;
		if(judge(m) == 1) j = m;
		else i = m;
	}
	return j;
}

int main(){
	cin >> N >> Q;
	for(int i=1; i<=N; i++) cin >> s[i];
	for(int i=0; i<Q; i++) cin >> t[i] >> d[i];
	cout << search_right() - search_left() << endl;
	return 0;
}
