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 ll = long long;
constexpr ll inf = static_cast<ll>(1e15);
constexpr ll mod = static_cast<ll>(1e9 + 7);

int n, q;
std::string s, ts, ds;
int main()
{
	std::cin >> n >> q;
	std::cin >> s;

	for (int i = 0; i < q; ++i) {
		char t, d;
		std::cin >> t >> d;
		ts += t;
		ds += d;
	}

	int l = 0, r = n - 1;
	for (int i = q - 1; i >= 0; --i) {
		if (ds[i] == 'L') {
			if (ts[i] == s[l])
				++l;
			if (r < n - 1 && ts[i] == s[r + 1])
				++r;
		}
		else {
			if (l > 0 && ts[i] == s[l - 1])
				--l;
			if (ts[i] == s[r])
				--r;
		}
	}

	std::cout << std::max(0, r - l + 1) << std::endl;
	return 0;
}
