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 Maxn 200000 + 5

int n,q;
char s[Maxn],t[Maxn],d[Maxn];

int Drop(int x){
	for(int i = 1;i <= q;i++){
		if (s[x] == t[i])
		   x += (d[i] == 'R') ? 1:-1;
		if (x > n) return -1;
		if (x < 1) return 1;
	}
	return 0;
}
int main(){
	cin >> n >> q;
	for(int i = 1;i <= n;i++)
		cin >> s[i];
	for(int i = 1;i <= q;i++)
		cin >> t[i] >> d[i];
	int l = 1,r = n,la = 0,ra = n + 1;
	while(l <= r){
		int mid = (l + r) >> 1;
		if (Drop(mid) == 1)
			la = mid,l = mid + 1;
		else
			r = mid - 1;			
	}
	l = 1,r = n;
	while(l <= r) {
		int mid = (l + r) >> 1;
		if (Drop(mid) == -1)
			ra = mid,r = mid - 1;
		else 
			l = mid + 1;
	}	
	cout << ra - la - 1 << endl;
	return 0;	
}