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<functional>
#include<utility>
#include<cmath>
#include<iomanip>
#include<algorithm>
#include<string>
#include<vector>
using namespace std;
int n, q;
vector<char> t(200010);
vector<char> d(200010);
string s;


int main() {
	cin >> n >> q >> s;
	for (int i = 0; i < q; i++)
	{
		cin >> t[i] >> d[i];
	}
	int beg = -1;
	int end = n;
	//呪文配列を後ろから操作
	for (int i = q-1; i >=0; i--)
	{
		if (beg>=-1&&t[i] == s[beg+1] && d[i] == 'L') {
			beg++;
		}
		if (beg>=0&&t[i] == s[beg] && d[i] == 'R') {
			beg--;
		}
		if (beg == n - 1) {
			break;
		}
	}
	for (int i = q - 1; i >= 0; i--)
	{
		if (end<=n&&t[i] == s[end-1] && d[i] == 'R') {
			end--;
		}
		if (end<=n-1&&t[i] == s[end] && d[i] == 'L') {
			end++;
		}
		if (end == 0) {
			break;
		}
	}
	int ans = 0;
	if (beg>=end)
	{
		ans = 0;
	}else {
		ans = end - beg - 1;
	}
	cout << ans << endl;
}