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+7;
int n,q,l,r,ans1,ans2;
string s;
char t[N],d[N];
int main(){
	ios::sync_with_stdio(false);
	cin>>n>>q;cin>>s;for(int i=1;i<=q;i++)cin>>t[i]>>d[i];
	l=0;r=n-1;ans1=-1;
	while(l<=r){
		int mid=(l+r)>>1,no=mid;
		for(int i=1;i<=q;i++){
			if(no<0)break;if(no==n)break;
			if(t[i]==s[no]){
				if(d[i]=='L')no--;
				else no++;
			}
		}
		if(no<0){ans1=mid;l=mid+1;}
		else r=mid-1;
	}
	l=0;r=n-1;ans2=n;
	while(l<=r){
		int mid=(l+r)>>1,no=mid;
		for(int i=1;i<=q;i++){
			if(no<0)break;if(no==n)break;
			if(t[i]==s[no]){
				if(d[i]=='L')no--;
				else no++;
			}
		}
		if(no==n){ans2=mid;r=mid-1;}
		else l=mid+1;
	}
	if(ans2<ans1)cout<<0<<endl;
	else cout<<ans2-ans1-1<<endl;
	return 0;
}