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>

#define INF INT_MAX
#define ll long long
#define REP(i,n) for(int i=0;i<n;i++)

using namespace std;

int n,q;

bool isRange(int a){
	return 0 <= a && a < n; 
}

int main(){
	cin.tie(0);
  	ios::sync_with_stdio(false);

	cin >> n >> q;

	string s;
	cin >> s;

	vector<pair<char,char>> td;
	int t,d;
	for(int i=0;i < q;i++){
		char t,d;
		cin >> t >> d;
		td.push_back(make_pair(t,d));
	}

	int l = -1;
	int r = n;
	for(int i = td.size()-1;i >= 0;i--){
		char t = td[i].first, d = td[i].second;
		// cout << t << " " << d << " " << s[l+1] << " " << s[r-1] << endl;
		if(isRange(l+1) && s[l+1] == t && d == 'L'){
			l++;
		}else if(isRange(l) && s[l] == t && d == 'R'){
			l--;
		}
		if(isRange(r-1) && s[r-1] == t && d == 'R'){
			r--;
		}else if(isRange(r) && s[r] == t && d == 'L'){
			r++;
		}
	}
	// cout << l << " " << r << endl;
	cout << n-(l+1)-(n-r) << endl;
   
	return 0;
}
