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<stdio.h>
char s[200010];
char t[200010],d[200010];
int n,q;
int go(int x){
	for(int i=1;i<=q;i++){
		if(t[i]==s[x])x+=(d[i]=='L'?-1:1);
	}
	return x;
}
int main(){
	int i,l,r,mid,res;
	char t1[10],t2[10];
	scanf("%d%d%s",&n,&q,s+1);
	for(i=1;i<=q;i++){
		scanf("%s%s",t1,t2);
		t[i]=t1[0];
		d[i]=t2[0];
	}
	res=n;
	l=1;
	r=n;
	while(l<r){
		mid=(l+r)>>1;
		if(go(mid))
			r=mid;
		else
			l=mid+1;
	}
	if(go(l))l--;
	res-=l;
	l=1;
	r=n;
	while(l<r){
		mid=(l+r)>>1;
		if(go(mid)==n+1)
			r=mid;
		else
			l=mid+1;
	}
	if(go(l)<=n)l++;
	res-=n-l+1;
	printf("%d",res);
}