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 main(){
	int N,Q;string s;cin>>N>>Q>>s;
	char T[Q],D[Q];
	for(int i=0;i<Q;i++){
		cin>>T[i]>>D[i];
	}int a=0,b=N+1;int k;
	int c,d;
	while(a+1<b){
		k=(a+b)/2;
		for(int j=0;j<Q;j++){
			if(T[j]==s.at(k-1)){
				if(D[j]=='L'){
					k--;
				}else{
					k++;
				}if(k==0||k==N+1){
                    break;
                }
			}
		}if(k==0){
			a=(a+b)/2;
		}else{
			b=(a+b)/2;
		}
	}c=a;
	a=0;b=N+1;
	while(a+1<b){
		k=(a+b+1)/2;
		for(int j=0;j<Q;j++){
			if(T[j]==s.at(k-1)){
				if(D[j]=='L'){
					k--;
				}else{
					k++;
				}if(k==0||k==N+1){
                    break;
                }
			}
		}if(k==N+1){
			b=(a+b+1)/2;
		}else{
			a=(a+b+1)/2;
		}
	}d=b;
	cout<<d-c-1<<endl;
}