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<iomanip>
//#include<cstdio>
#include<vector>
#include<map>
#include<queue>
#include<algorithm>
#include<cmath>
#include<cassert>
using namespace std;
typedef long long ll;
const int Qmax = 2e5;
int N, Q;
string S;
char T[Qmax], D[Qmax];

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

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

	// cout << r-l+1 << " " << l << " " << r << endl;
	cout << r-l+1 << endl;

	return 0;
}
