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>

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

using namespace std;

const int INF=1<<29;

int main(){
	int n,q;
	string s; cin>>n>>q>>s;
	vector<char> c(q),dir(q);
	rep(i,q) cin>>c[i]>>dir[i];

	auto simulate=[&](int x){
		rep(i,q+1){
			if(x==-1) return -1;
			if(x== n) return  1;
			if(i<q && s[x]==c[i]) x+=(dir[i]=='L'?-1:1);
		}
		return 0;
	};

	int ans=n,lo=-1,hi=n;
	while(hi-lo>1){
		int mi=(lo+hi)/2;
		if(simulate(mi)==-1) lo=mi;
		else                 hi=mi;
	}
	ans-=lo+1;

	lo=-1; hi=n;
	while(hi-lo>1){
		int mi=(lo+hi)/2;
		if(simulate(mi)==1) hi=mi;
		else                lo=mi;
	}
	ans-=n-hi;

	cout<<ans<<'\n';

	return 0;
}
