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;
int n,q;
char s[300001],c[300001][5],d[300001][5];
int sim(int x)
{
	for(int i=1;i<=q;i++)
		if(s[x]==c[i][0])
		{
			if(d[i][0]=='L')x--;
			else x++;
			if(!x||x>n)return x;
		}
	return x;
}
int main()
{
	cin>>n>>q>>s+1;
	for(int i=1;i<=q;i++)cin>>c[i]>>d[i];
	int l=1,r=n,ansL=0,ansR=n+1;
	while(l<=r)
	{
		int m=(l+r)/2;
		if(!sim(m))ansL=m,l=m+1;
		else r=m-1;
	}
	l=1;r=n;
	while(l<=r)
	{
		int m=(l+r)/2;
		if(sim(m)>n)ansR=m,r=m-1;
		else l=m+1;
	}
	cout<<n-(ansL+n+1-ansR)<<'\n';
}
