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<cstdio>
#include<cctype>
inline char rdc(){
	char c=getchar();
	while(!isupper(c))c=getchar();
	return c;
}
const int N=200050;
char s[N],t[N];
int n,q;
bool opt[N];
inline bool check1(int p){
	for(int i=0;i<q;++i)if(s[p]==t[i])if(opt[i])if(!--p)return 1;
	else;
	else ++p;
	return 0;
}
inline bool check2(int p){
	for(int i=0;i<q;++i)if(s[p]==t[i])if(opt[i])--p;
	else if(++p>n)return 1;
	return 0;
}
int main(){
	int i,l=1,r,m,s1=0,s2;
	char c;
	scanf("%d%d%s",&n,&q,s+1);
	s2=(r=n)+1;
	for(i=0;i<q;++i){t[i]=rdc();opt[i]=rdc()=='L';}
	while(l<=r){
		m=l+r>>1;
		if(check1(m))l=(s1=m)+1;
		else r=m-1;
	}
	l=s1+1;r=n;
	while(l<=r){
		m=l+r>>1;
		if(check2(m))r=(s2=m)-1;
		else l=m+1;
	}
	printf("%d\n",s2-s1-1);
	return 0;
}