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 <iostream>
#include <cstdlib>
#include <string>
#include <set>
#include <vector>

using namespace std;

int n,q;
string str;
vector<pair<char, char> > req;

int judge(int x){
	for(auto &p: req){
		if(str[x] == p.first){
			if(p.second == 'L'){
				x--;
				if(x == -1)return 1;
			}else{
				x++;
				if(x == n)return -1;
			}
		}
	}
	return 0;
}

int main()
{
	cin >> n >> q;
	cin >> str;
	
	for(int i = 0 ; i < q; i++){
		char X;
		cin >> X;
		char lr;
		cin >> lr;
		req.push_back(make_pair(X, lr));
	}
	
	int l = 0, r = n;
	int m = (l + r) / 2;
	while(1){
		if(judge(m) > 0){
			l = m;
		}else{
			r = m;
		}
		m = (l + r) / 2;
		if(r - l == 1){
			break;
		}
	}
	//cout << r << endl;
	int start = r;
	
	l = 0, r = n;
	m = (l + r) / 2;
	while(1){
		if(judge(m) < 0){
			r = m;
		}else{
			l = m;
		}
		m = (l + r) / 2;
		if(r - l == 1){
			break;
		}
	}
	cout << r - start << endl;
}