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<iostream>
#include<string>
using namespace std;
#define N 200005

int n,q,ans;
string s;
char c[N];
bool dir[N];

bool to(int x,int to)
{
	for(int i=0;i<q;i++)
	{
		if(c[i]!=s[x]) continue;
		if(dir[i]) x++;
		      else x--;
		if(x==to) return 1;
		if(x==-1 || x==n) return 0;
	}
	return 0;
}

int main()
{
	
	cin>>n>>q;
	cin>>s;
	for(int i=0;i<q;i++)
	{
		cin>>c[i];
		char x;
		cin>>x;
		if(x=='R') dir[i]=1;
	}
	
	ans=n;
	int l=-1,r=n;
	while(l+1<r)
	{
		int mid=(l+r)/2;
		if(to(mid,-1)) l=mid;
		          else r=mid;
	}
	ans-=r;
	l=-1,r=n;
	while(l+1<r)
	{
		int mid=(l+r)/2;
		if(to(mid,n)) r=mid;
		         else l=mid;
	}
	ans-=n-r;
	cout<<ans<<'\n';
	
	return 0;
}