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;
#define int long long
#define rep(i,n) for(int i=0;i<n;i++)
int n,q,L,R;
string s;
char t[222222],d[222222];
signed main(){
	cin>>n>>q>>s;
	rep(i,q)cin>>t[i]>>d[i];
	int ok=-1,ng=n;
	while(ng-ok>1){
		int mid=(ok+ng)/2;
		int now=mid;
		rep(i,q){
			if(s[now]==t[i]){
				if(d[i]=='L')now--;
				else now++;
			}
			if(now==-1)break;
		}
		if(now==-1)ok=mid;
		else ng=mid;
	}
	L=ok;
	ng=-1,ok=n;
	while(ok-ng>1){
		int mid=(ok+ng)/2;
		int now=mid;
		rep(i,q){
			if(s[now]==t[i]){
				if(d[i]=='L')now--;
				else now++;
			}
			if(now==n)break;
		}
		if(now==n)ok=mid;
		else ng=mid;
	}
	R=ok;
	cout<<max(0ll,R-L-1)<<endl;
	return 0;
}
