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>

using namespace std;

string s;
int n, q;
char c[200005], d[200005];

bool probaj(int x, bool p){
	for(int i = 0 ; i < q ; ++i){
		if(s[x] == c[i]){
			if(d[i] == 'L'){
				x--;
			}
			else{
				x++;
			}
			if(x <= 0 && !p)
				return 1;
			if(x > n && p)
				return 1;
		}
	}
	return 0;
}

int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n >> q;
cin >> s;
s = "$" + s + "$";
for(int i = 0 ; i < q ; ++i){
	cin >> c[i] >> d[i];
}
int l = 1, r = n;
while(l <= r){
	int mid = (l + r) / 2;
	if(!probaj(mid, 0)){
		r = mid - 1;
	}
	else{
		l = mid + 1;
	}
}
//cout << l << ' ' << r << endl;
int sol = r;
l = 1;
r = n;
while(l <= r){
	int mid = (l + r) / 2;
	if(!probaj(mid, 1)){
		l = mid + 1;
	}
	else{
		r = mid - 1;
	}
}
sol += (n + 1 - l);
sol = n - sol;
cout << sol << endl;

return 0;
}

