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;

void solve(void)
{
	int n, q;
	string s;
	cin >> n >> q >> s;
	vector<char> ts(q), ds(q);
	for (int i = 0; i < q; i++)
	{
		cin >> ts[i] >> ds[i];
	}
	int l = -1, r = n;
	while(l+1<r)
	{
		int m = (l + r) / 2, p = m;
		char t = s[p];
		for (int i = 0; i < q; i++)
		{
			if (ts[i] == t)
			{
				if (ds[i] == 'L')
				{
					p--;
				}
				else p++;
			}
			if (p < 0 || p >= n) break;
			t = s[p];
		}
		if (p < 0) l = m;
		else r = m;
	}
	int ans = n - l - 1;
	l = -1, r = n;
	while(l+1<r)
	{
		int m = (l + r) / 2, p = m;
		char t = s[p];
		for (int i = 0; i < q; i++)
		{
			if (ts[i] == t)
			{
				if (ds[i] == 'L')
				{
					p--;
				}
				else p++;
			}
			if (p < 0 || p >= n) break;
			t = s[p];
		}
		if (p >= n) r = m;
		else l = m;
	}
	ans -= n - r;
	cout << ans << endl;
}

int main(void)
{
	solve();
	//cout << "yui(*-v・)yui" << endl;
	return 0;
}
