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;
int n,q;
char s[300000];
char t[300000];
char d[300000];
int pos(int u) {
	int i=0;
	while(u>=0 && u<n && i<q) {
		if(s[u]==t[i]) {
			if(d[i]=='L') u--;
			else u++;
		}
		i++;
	}
	if(u==-1) return -1;
	if(u==n) return 1;
	return 0;
}
int main()
{
	scanf("%d %d",&n,&q);
	scanf("%s",s);
	char ch[2][2];
	for(int i=0;i<q;i++) {
		scanf("%s %s",ch[0],ch[1]);
		t[i]=ch[0][0];
		d[i]=ch[1][0];
	}
	/*pos(1);
	return 0;*/
	int l=0;
	int r=n-1;
	int ans=n;
	while(l<r) {
		int mid=(l+r+1)>>1;
		if(pos(mid)==-1) l=mid;
		else r=mid-1;
	}
	while(l>=0 && pos(l)>=0) l--;
	//printf("%d\n",l);
	ans-=(l+1);
	l=0;
	r=n-1;
	while(l<r) {
		int mid=(l+r)>>1;
		if(pos(mid)==1) r=mid;
		else l=mid+1;
	}
	while(r<n && pos(r)<=0) r++;
	//printf("%d\n",pos(r));
	ans-=(n-r);
	printf("%d",ans);
	return 0;
}