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;
using nagai = long long;
#define sz(x) int((x).size())

const int N=250250;
char ts[N];
int dir[N];

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n,q;
	cin>>n>>q;
	string s;
	cin>>s;
	for(int i=0;i<q;++i){
		 char s;
		 char c;
		 cin>>s>>c;
		 ts[i]=s;
		 dir[i]=c=='R'?1:-1;
	}
	int L=-1,R=n;
	while(R-L>1){
		int M=(L+R)/2;
		int cur=M;
		bool ok=false;
		for(int i=0;i<q;++i){
			 if(s[cur]==ts[i])
				 cur+=dir[i];
			 if(cur==n)
				 break;
			 if(cur==-1){
				  ok=true;
				  break;
			 }
		}
		if(ok)L=M;
		else R=M;
	}
	int kek=L;
	L=-1,R=n;
	while(R-L>1){
		int M=(L+R)/2;
		int cur=M;
		bool ok=false;
		for(int i=0;i<q;++i){
			 if(s[cur]==ts[i])
				 cur+=dir[i];
			 if(cur==-1)
				 break;
			 if(cur==n){
				  ok=true;
				  break;
			 }
		}
		if(ok)R=M;
		else L=M;
	}
	if(kek>=R)cout<<0<<'\n';
	else cout<<R-kek-1<<'\n';
	return 0;
}

