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 <vector>
#include <algorithm>
#include <queue>
using namespace std;
char dt[200001][2]={};
int n,q,l,r,tl,tr;string s;
bool ps(int idx,int ck)
{
	int cr = idx;
	for (int i=0;i<q;i++)
	{
		if (cr<0||cr>=n) {break;}
		if (dt[i][0]==s[cr])
		{
			if (dt[i][1]=='L') {cr--;}
			else {cr++;}
		}
	}
	if (ck&&cr<0) {return true;}
	else if (!ck&&cr>=n) {return true;}
	else {return false;}
}
int main()
{
	cin>>n>>q>>s;
	for (int i=0;i<q;i++)
	{
		cin>>dt[i][0]>>dt[i][1];
	}
	l=0,r=n;
	while (l<r)
	{
		int pv = (l+r)>>1;
		if (ps(pv,1)) {l=pv+1;}
		else {r=pv;}
	}
	tl = l;
	l=0;r=n;
	while (l<r)
	{
		int pv = (l+r)>>1;
		if (ps(pv,0)) {r=pv;}
		else {l=pv+1;}
	}
	tr = l;
	//cout<<tl<<" "<<tr<<"\n";
	cout<<tr-tl<<"\n";
	return 0;
}