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;
char t[200010],d[200010];
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
	int i,n,q;
	string s;
	cin >> n >> q >> s;
	for(i=0;i<q;i++){
		cin >> t[i] >> d[i];
	}
	int l = -1,r = n;
	for(i=q-1;i>=0;i--){
		if(d[i]=='L'){
			if(l<n-1 && s[l+1]==t[i]) l++;
			if(r<n && s[r]==t[i]) r++;
		}else{
			if(r>0 && s[r-1]==t[i]) r--;
			if(l>=0 && s[l]==t[i]) l--;
		}
	}
	cout << max(0,r - l - 1) << endl;
}