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
//保持物品顺序不变（显然），那么，二分边界就可以了 
#include<iostream>
using namespace std;
const int N=2e5+10;
int n,Q;
char s[N],t[N],d[N];
int check(int x)
{
	for(int i=1;i<=Q;i++)
	{
		if(s[x]==t[i]) x+=(d[i]=='R')?1:-1;
		if(x>n) return -1;
		if(x<1) return 1;
	}
	return 0;
}
int main()
{
	cin>>n>>Q;
	scanf("%s",s+1);
	for(int i=1;i<=Q;i++) cin>>t[i]>>d[i];
	int l=1,r=n,la=0,ra=n+1;
	while(l<=r)
	{
		int mid=(l+r)>>1;
		if(check(mid)==1) la=mid,l=mid+1;
		else r=mid-1;
	}
	l=1,r=n;
	while(l<=r)
	{
		int mid=(l+r)>>1;
		if(check(mid)==-1) ra=mid,r=mid-1;
		else l=mid+1;
	}
	cout<<ra-la-1<<endl;
}