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;
#define repp(i,a,b) for(int i = (int)(a) ; i < (int)(b) ; ++i)
#define repm(i,a,b) for(int i = (int)(a) ; i > (int)(b) ; --i)

int main(){
	int N,Q; cin >> N >> Q;
	string S; cin >> S;
	S = "*"+S+"*";
	int x = 0, y = N+1;
	int l = 0, r = N+1;
	vector<char> t(Q),d(Q);
	repp(i,0,Q) cin >> t[i] >> d[i];
	repm(i,Q-1,-1){
		if(d[i] == 'L'){
			if(S[l+1] == t[i]) ++l;
			if(S[r] == t[i]) ++r;
		} else {
			if(S[l] == t[i]) --l;
			if(S[r-1] == t[i]) --r;
		}
		x = max(x,l);
		y = min(y,r);
	}
	cout << N-min(N,l+N+1-r) << endl;
	return 0;
}
