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;
int main() {
	int n, q; cin >> n >> q;
	string s; cin >> s;
	vector<char> t(q), d(q);
	vector<int> e(q);
	for(int i=0;i<q;i++){
		cin >> t[i] >> d[i];
		if(d[i]=='L'){
			e[i] = -1;
		}else{
			e[i] = 1;
		}
	}
	if(n==1){
		for(int i=0;i<q;i++){
			if(s[0]==t[i]){
				cout << 0 << endl;
				return 0;
			}
		}
		cout << 1 << endl;
		return 0;
	}
	int ok = -1;
	int ng = n;
	while(ng-ok>1){
		int c = (ok+ng)/2;
		int now = c;
		for(int i=0;i<q;i++){
			if(s[now]==t[i]){
				now += e[i];
			}
			if(now<0) break;
		}
		if(now<0){
			ok = c;
		}else{
			ng = c;
		}	
	}
	int left = ng;

	ng = -1;
	ok = n;
	while(ok-ng>1){
		int c = (ok+ng)/2;
		int now = c;
		for(int i=0;i<q;i++){
			if(s[now]==t[i]){
				now += e[i];
			}
			if(now>n-1) break;
		}
		if(now>n-1){
			ok = c;
		}else{
			ng = c;
		}	
	}
	int right = ng;
	cout << right-(left-1) << endl;
	return 0;
}