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>
int main( void )
{
	int N, Q ;
	scanf("%d %d\n", &N, &Q ) ;
	char S[200000+2];
	scanf("%s\n", &S[1] ) ;
	S[0]='\0';
	char t[200000],d[200000];
	for( int n = 0 ; n < Q ; n++ ) {
		scanf("%c %c\n", &t[n], &d[n] ) ;
	}
	int l=0,r=N+1;
	for( int n=Q-1 ; n >= 0 ; n-- ) {
		if( d[n]=='L' ) {
			if( t[n] == S[l+1]) l++ ;
			if( t[n] == S[r]) r++ ;
		} else {
			if( t[n] == S[r-1]) r-- ;
			if( t[n] == S[l]) l-- ;
		}
	}
	int c=r-l-1;
	printf("%d\n", c<0?0:c ) ;
	return 0 ;
}

