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;
typedef pair<int,int> P;

int N, Q;
string s;

char t[200005], d[200005];

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin >> N >> Q >> s;

	for (int i = 0;i < Q;i++){
		cin >> t[i] >> d[i];
	}

	int idx = -1;
	for (int i = Q-1;i >= 0;i--){
		if(idx != N-1 && s[idx+1] == t[i] && d[i] == 'L'){
			idx++;
		}else if(idx != -1 && s[idx] == t[i] && d[i] == 'R'){
			idx--;
		}
	}

	int ans = idx+1;

	idx = N;
	for (int i = Q-1;i >= 0;i--){
		if(idx != 0 && s[idx-1] == t[i] && d[i] == 'R'){
			idx--;
		}else if(idx != N && s[idx] == t[i] && d[i] == 'L'){
			idx++;
		}
	}

	ans += N-idx;

	cout << max(0,N-ans) << endl;

	return 0;

}
