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>
#include <algorithm>
#include <stack>
using namespace std; 
int main(){
	int N, Q; cin >> N >> Q; 
	string S;
	cin >> S; 
	char T[200010] = {}; 
	char D[200010] = {}; 
	for(int i = 0; i < Q; i++){
		cin >> T[i] >> D[i]; 
	}
	int left = 0; int right = N; //左右から落ちる境界
	for(int i = Q - 1; i >= 0; i--){
		if(D[i] == 'L' && left <= N-1 && T[i] == S.at(left)){
			left ++; 
		} 
      	else if(D[i] == 'R' && left >= 1 && T[i] == S.at(left-1)){
			left --; 
		} 
		if(D[i] == 'R' && right >= 1 && T[i] == S.at(right-1)){
			right --; 
		} 
      	else if(D[i] == 'L' && right <= N-1 && T[i] == S.at(right)){
			right ++; 
		} 
      //cout << left << " " << right << endl; 
	} 
	cout << right - left << endl; 
}