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 <map>

using namespace std;

struct M {
	char t, d;
};

int main() {
	long long n, q;
	cin >> n >> q;
	
	string s;
	cin >> s;
	
	vector<M> m(q);
	for (auto &&e : m) {
		cin >> e.t >> e.d;
	}
	
	long long lCount = 0, rCount = 0;
	for (long long i = q - 1; i >= 0; --i) {
//		cout << m[i].t << " " << m[i].d << endl;
		if (m[i].d == 'L') {
			if (s[lCount] == m[i].t) {
				++lCount;
//				cout << "++L" << endl;
			}
			
			if (rCount && s[n - rCount] == m[i].t) {
				--rCount;
			}
		} else {
			if (s[n - 1 - rCount] == m[i].t) {
				++rCount;
//				cout << "++R" << endl;
			}
		
			if (lCount && s[lCount - 1] == m[i].t) {
				--lCount;
			}
		}
	}
	
	cout << n - (lCount + rCount) << endl;
}