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>
using namespace std;
char t[200000],d[200000];
int n,q;
string s;

int simulate(int x){
	for(int i=0;i<q;i++){
		if(s[x]==t[i]){
			if(d[i]=='L') x--;
			else x++;
			if(x<0 || n<=x) break;
		}
	}
	return x;
}

int main(){
	cin >> n >> q;
	cin >> s;
	for(int i=0;i<q;i++) cin >> t[i] >> d[i];

	int left=-1,right=n;
	while(left+1<right){
		int mid=(left+right)/2;
		int p=simulate(mid);
		if(p==-1) left=mid;
		else right=mid;
	}
	int l=left;
	left=-1,right=n;
	while(left+1<right){
		int mid=(left+right)/2;
		int p=simulate(mid);
		if(p==n) right=mid;
		else left=mid;
	}
	int r=right;
	cout << n-((l+1)+(n-r)) << endl;
	return 0;
}
