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 rep(i,n) for(int i=0;i<n;i++)
#define int long long
typedef pair<int, int> P;
string s; 
char t[200006], d[200006];
int n, q; 
int simul(int x) {
	rep(i, q) {
		if (t[i] == s[x]) {
			if (d[i] == 'L')x--; else x++;
			if (x < 0 || x == n)return x;
		}
	}
	return x;
}

signed main() {
	cin >> n >> q;
	cin >> s;
	rep(i, q)cin >> t[i] >> d[i];

	int lb = -1, ub = n;
	while (ub - lb > 1) {
		int mi = (ub + lb) / 2;
		if (simul(mi) == -1)lb = mi;
		else ub = mi;
	}
	int lb2 = -1, ub2 = n;
	while (ub2 - lb2 > 1) {
		int mi = (ub2 + lb2) / 2;
		if (simul(mi) == n)ub2 = mi;
		else lb2 = mi;
	}
	cout << n - (lb + 1) - (n - ub2) << endl;
}