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;

int n,q,ans = 0;
char t[200010],d[200010];
string s;

bool C(int x){
	for(int i = 0;i < q;i++){
		if(s[x] == t[i]){
			x += (d[i] == 'L') ? -1 : 1;
		}
		if(x < 0) return true;
		if(x >= n) return false;
	}
	return false;
}

signed main(){
	cin >> n >> q >> s;
	for(int i = 0;i < q;i++){
		cin >> t[i] >> d[i];
	}
	for(int a = 0;a < 2;a++){
		int low = -1,up = n;
		while(up - low > 1){
			int mid = (up + low) / 2;
			if(C(mid)) low = mid;
			else up = mid;
		}
		ans += low + 1;
		reverse(s.begin(),s.end());
		for(int i = 0;i < q;i++){
			d[i] = ((d[i] == 'L') ? 'R' : 'L');
		}
	}
	cout << n - ans << endl;
}
