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 <iostream>
#include <iomanip>
#include <ios> 
#include <vector>
#include <string>
#include <algorithm>
#include <functional>
#include <queue>
#include <stack>
#include <set>
#include <cmath>
#include <bitset>
#include <map>
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define sz(c) ((int)(c).size())

using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
const int MAX=2e5+5;

int main(){
	int N,Q;
	cin>>N>>Q;
	char s[MAX],t[MAX],d[MAX];
	s[0]='0',s[N+1]='0';
	rep1(i,N)cin>>s[i];
	rep1(i,Q)cin>>t[i]>>d[i];
	int x=0,y=N+1;
	for(int i=Q;i>=1;i--){
		if(s[x+1]==t[i]&&d[i]=='L')x++;
		if(s[x]==t[i]&&d[i]=='R')x--;
		if(s[y-1]==t[i]&&d[i]=='R')y--;
		if(s[y]==t[i]&&d[i]=='L')y++;
	}
	cout<<max(0, y-x-1)<<endl;
}