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 <vector>
#include <string>
#include <algorithm>

using namespace std;

int n,q;
string str;

int main() {
	cin >> n >> q;
	cin >> str;
	vector<pair<char,char> > arr(q);
	for(int i = 0; i < q; i++) {
		cin >> arr[i].first >> arr[i].second;
	}
	reverse(arr.begin(),arr.end());
	int l = 0;
	int r = n;
	for(pair<char,char> p : arr) {
		char al = p.first;
		char op = p.second;
		//cout << al << "," << op << endl;
		if(l<str.size() && str[l]==al && op=='L') {
			l++;
		}else if(l>0&&str[l-1]==al&&op=='R') {
			l--;
		}
		if(r>0 && str[r-1]==al && op=='R') {
			r--;
		}else if(r<str.size()&&str[r]==al&&op=='L') {
			r++;
		}
		//cout << l << "," << r << endl;
	}
	int ans = max(0,r-l);
	cout << ans << endl;

}
