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;

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

    int N, Q;
    string S;
    char T[200000], D[200000];
    cin >> N >> Q >> S;

    for(int i = 0; i < Q; i++) cin >> T[i] >> D[i];

	int L = 0;
	int R = N;
	for(int i = Q - 1; i >= 0; i--){
		if (R > 0 && D[i] == 'R' && S[R - 1] == T[i]) R--;
		else if (R < N && D[i] == 'L' && S[R] == T[i]) R++;
		if (L > 0 && D[i] == 'R' && S[L - 1] == T[i]) L--;
		else if (L < N && D[i] == 'L' && S[L] == T[i]) L++;
	}

	cout << R - L << endl;

	return 0;
}
