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>
using namespace std;
int main(){
	int N, Q;
	cin >> N >> Q;
	string s;
	cin >> s;
	vector<char> t(Q), d(Q);
	for (int i = 0; i < Q; i++){
		cin >> t[i] >> d[i];
	}
	int t1 = -1;
	int f1 = N;
	while (f1 - t1 > 1){
		int mid = (t1 + f1) / 2;
		int pos = mid;
		for (int i = 0; i < Q; i++){
			if (s[pos] == t[i]){
				if (d[i] == 'L'){
					pos--;
				} else {
					pos++;
				}
			}
			if (pos == -1 || pos == N){
				break;
			}
		}
		if (pos == -1){
			t1 = mid;
		} else {
			f1 = mid;
		}
	}
	int t2 = N;
	int f2 = -1;
	while (t2 - f2 > 1){
		int mid = (t2 + f2) / 2;
		int pos = mid;
		for (int i = 0; i < Q; i++){
			if (s[pos] == t[i]){
				if (d[i] == 'L'){
					pos--;
				} else {
					pos++;
				}
			}
			if (pos == -1 || pos == N){
				break;
			}
		}
		if (pos == N){
			t2 = mid;
		} else {
			f2 = mid;
		}
	}
	cout << t2 - t1 - 1 << endl;
}