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 int long long
#define END getchar();getchar();return 0
#define rep(i,n) for(int i=0;i<n;i++)
#define inf 1000000007
typedef pair<int, int> P;
char t[250000], d[250000];

signed main() {
	int n, q, ans = 0;
	cin >> n >> q;
	string s;
	cin >> s;
	for (int i = 0; i < q; i++) {
		cin >> t[i] >> d[i];
	}
	int a = s.size() - 1;
	for (int i = q - 1; i >= 0; i--) {
		if (d[i] == 'R'&&s[a]==t[i]){
			ans++;
			a--;
		}
		if (ans&&d[i] == 'L'&&t[i] == s[a+1]){
			ans--;
			a++;
		}
	}
	a = 0;
	n -= ans;
	ans = 0;
	for (int i = q - 1; i >= 0; i--) {
		if (d[i] == 'L'&&s[a]==t[i]){
			ans++;
			a++;
		}
		if (ans&&d[i] == 'R'&&t[i] == s[a-1]){
			ans--;
			a--;
		}
	}
	cout << n - ans << endl;

	END; 
}
