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,m,L,R;
char s[300000],a[300000][1],b[300000][1];

int main(){
	scanf("%d%d%s",&n,&m,s+1);
	for (int i=1;i<=m;++i){
		scanf("%s%s",a[i],b[i]);
	}
	int l=1,r=n; L=0;
	while (l<=r){
		int mid=(l+r)>>1;
		int x=mid;
		for (int i=1;i<=m;++i){
			if (s[x]==a[i][0]){
				if (b[i][0]=='L') --x;
				else ++x;
			}
			if (!x||x>n) break;
		}
		if (x==0){L=mid; l=mid+1;}
		else r=mid-1;
	}
	l=1,r=n; R=n+1;
	while (l<=r){
		int mid=(l+r)>>1;
		int x=mid;
		for (int i=1;i<=m;++i){
			if (s[x]==a[i][0]){
				if (b[i][0]=='L') --x;
				else ++x;
			}
			if (!x||x>n) break;
		}
		if (x>n){R=mid; r=mid-1;}
		else l=mid+1;
	}
	printf("%d\n",n-(L+(n-R+1)));
	
	return 0;
}
			