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;
const int N=2e5+10;
int n,m;
char s[N],si[N][2],di[N][2];

bool check(int mid,int k) {
	if (mid<1 || mid>n) return 1;
	for (int i=1;i<=m;i++) {
		if (s[mid]!=si[i][0]) continue;
		if (di[i][0]=='L') mid--; else mid++;
		if (k==1) if (mid<1) return 1;
		if (k==2) if (mid>n) return 1;
	}
	return 0;
}

int main()
{
	cin>>n>>m;
	scanf("%s",s+1);
	for (int i=1;i<=m;i++) scanf("%s%s",&si[i],&di[i]);
	
	int L=0,R=n,ans=0;
	while (L<R) {
		int mid=L+R+1>>1;
		if (check(mid,1)) L=mid; else R=mid-1;
	}
	ans+=L;
	
	L++; R=n+1;
	while (L<R) {
		int mid=L+R>>1;
		if (check(mid,2)) R=mid; else L=mid+1;
	} 
	ans+=(n-R+1);
	
	cout<<n-ans<<endl;
	return 0;
}