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>
using namespace std;
int main()
{
	int N, Q;
	cin >> N >> Q;
	string s;
	cin >> s;
	vector<char> t(Q);
	vector<char> d(Q);
	for(int i = 0; i < Q; i += 1)
	{
		cin >> t[i] >> d[i];
	}

	int left = 0, right = N - 1;
	for(int i = Q - 1; i >= 0; i -= 1)
	{
		if(s[left] == t[i] && d[i] == 'L')
		{
			left += 1;
		}
		else if(s[right] == t[i] && d[i] == 'R')
		{
			right -= 1;
		}

		if(left > 0 && s[left - 1] == t[i] && d[i] == 'R')
		{
			left -= 1;
		}
		else if(right < N - 1 && s[right + 1] == t[i] && d[i] == 'L')
		{
			right += 1;
		}

		if(left > right)
			break;
	}

	std::cout << std::to_string(right - left + 1) << std::endl;
	return 0;
}