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>
#define int long long
#define P pair<int,int>
#define PP pair<int,P>
#define F first
#define S second
#define f(i,n) for(int i=0;i<(n);i++)
#define INF LLONG_MAX/3
#define eps LDBL_EPSILON
#define mod (int)(1000000007)
#define pie 3.141592653589793238462643383279
#define Bpri priority_queue
#define Spri priority_queue<P,vector<P>,greater<P>>
using namespace std;
char x[200000],y[200000];
signed main(){
	int a,b,c=-1,d;
	string s;
	cin>>a>>b>>s;
	d=a;
	f(i,b){
		cin>>x[i]>>y[i];
	}
	for(int i=b-1;i>=0;i--){
		if(x[i]==s[c+1]&&y[i]=='L')c++;
		if(x[i]==s[d-1]&&y[i]=='R')d--;
		if(x[i]==s[c]&&y[i]=='R')c--;
		if(x[i]==s[d]&&y[i]=='L')d++;
	}
	cout<<max((int)(0),d-c-1)<<endl;
    return 0;
}
