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;

#define REP(i,n) for(int i=0;i<(int)(n);i++)

int n,q;
char s[252521];
char t[252521], d[252521];

int main(){
	scanf("%d%d",&n,&q);
	scanf("%s",s);
	REP(i,q)scanf("%s%s",t+i,d+i);
	int rp, lp;
	int ok = -1, ng = n;
	while(abs(ok-ng)>1){
		int x = (ok+ng)/2;
		bool right = false;
		int p = x;
		REP(i,q)if(s[p]==t[i]){
			p += d[i]=='R' ? +1 : -1;
			if(p==n){
				right = true;
				break;
			}
		}
		if(right){
			ng = x;
		}else{
			ok = x;
		}
	}
	rp = ok;
	ok = n, ng = -1;
	while(abs(ok-ng)>1){
		int x = (ok+ng)/2;
		bool left = false;
		int p = x;
		REP(i,q)if(s[p]==t[i]){
			p += d[i]=='R' ? +1 : -1;
			if(p==-1){
				left = true;
				break;
			}
		}
		if(left){
			ng = x;
		}else{
			ok = x;
		}
	}
	lp = ok;
	printf("%d\n",rp-lp+1);
	return 0;
}