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;
	cin>>N>>Q;
	string S;
	cin>>S;
	
	vector<pair<char,char>> pa(Q);
	
	for(int i=0;i<Q;i++){
		char t,d;
		cin>>t>>d;
		pa[i]=make_pair(t,d);
	}
	reverse(pa.begin(),pa.end());
	int out_zone_f = -1;
	int out_zone_e = N;
	for(int i=0;i<Q;i++){
		char t=pa[i].first;
		char d=pa[i].second;
		if(d=='L'){
			if(S[out_zone_f+1]==t)out_zone_f++;
			if(out_zone_e!=N){
				if(S[out_zone_e]==t)out_zone_e++;
			}
		}
		else{
			if(S[out_zone_e-1]==t)out_zone_e--;
			if(out_zone_f!=-1){
				if(S[out_zone_f]==t)out_zone_f--;
			}
		}
	}
	int out = (out_zone_f+1)+(N-out_zone_e);
	cout<<N-out<<endl;
	
	return 0;
}
