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 ll long long
#define N 200010
using namespace std;
char get(){
	char ch=getchar();
	while (ch<'A'||ch>'Z') ch=getchar();
	return ch;
}
int n,q;
char ch[N];
struct Info{char x,y;}qu[N];
int main(){
	cin>>n>>q;
	for (int i=1;i<=n;i++)ch[i]=get();
	for (int i=1;i<=q;i++){qu[i].x=get();qu[i].y=get();}
	int l=1,r=n;
	for (int i=q;i>=1;i--){
		if (qu[i].y=='L'){
			if (ch[l]==qu[i].x) l++;
			if (r!=n&&ch[r+1]==qu[i].x) r++;
		}else{
			if (ch[r]==qu[i].x) r--;
			if (l!=1&&ch[l-1]==qu[i].x) l--;
		}
	}
	cout<<r-l+1<<endl;
	return 0;
}