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<algorithm>
#include<vector>
using namespace std;
int n,q;
string s;
vector<pair<char,bool> >a;
int main()
{
	cin>>n>>q>>s;
	for(int i=0;i<q;i++)
	{
		char t,d;cin>>t>>d;
		a.push_back(make_pair(t,d=='R'));
	}
	int L=0;
	for(int i=q;L<n&&i--;)
	{
		if(a[i].second)
		{
			if(L>0&&a[i].first==s[L-1])
			{
				L--;
			}
		}
		else
		{
			if(a[i].first==s[L])L++;
		}
	}
	L--;
	int R=n-1;
	for(int i=q;R>=0&&i--;)
	{
		if(a[i].second)
		{
			if(a[i].first==s[R])R--;
		}
		else
		{
			if(R<n-1&&a[i].first==s[R+1])
			{
				R++;
			}
		}
	}
	R++;
	cout<<max(0,n-L-1-(n-R))<<endl;
}