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;

#define LL long long

#define FOR(INDEX, START, END) for (LL INDEX = (START); INDEX < (END); ++INDEX)
#define REP(INDEX, COUNT) for (LL INDEX = 0; INDEX < (COUNT); ++INDEX)

struct Data {
	char t, d;
};

int main()
{
	LL N, Q;
	cin >> N >> Q;

	string S;
	cin >> S;

	vector<int> isOuts(N, 0);

	vector<Data> qs(Q);

	REP(i, Q) {
		cin >> qs[i].t >> qs[i].d;
	}
	
	int left = 0;
	int right = N - 1;

	REP(ri, Q) {
		int i = Q - 1 - ri;

		if (qs[i].d == 'L') {
			if (S[left] == qs[i].t) {
				left++;
			}

			if (right + 1 < N && S[right + 1] == qs[i].t) {
				right++;
			}
		}
		if (qs[i].d == 'R') {
			if (S[right] == qs[i].t) {
				right--;
			}

			if (left - 1 >= 0 && S[left - 1] == qs[i].t) {
				left--;
			}
		}
	}

	int total = right - left + 1;
	if (total < 0) {
		total = 0;
	}

	cout << total << endl;

	return 0;
}
