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<cmath>
#include<algorithm>
#include<string>
using namespace std;

#define SIZE 200005

int n,m;
string str;
char mo[SIZE],dr[SIZE];
int ch[SIZE],d[SIZE];
int i,j,k;

bool left(int p){
  for(i=0;i<m;i++){
    if(str[p]-'A'==ch[i]){
      p+=d[i];
      if(p<0) return true;
      if(p>=n) return false;
    }
  }
  return false;
}

bool right(int p){
  for(i=0;i<m;i++){
    if(str[p]-'A'==ch[i]){
      p+=d[i];
      if(p>=n) return true;
      if(p<0) return false;
    }
  }
  return false;
}

int main(){
  cin>>n>>m;
  cin>>str;
  for(i=0;i<m;i++){
    cin>>mo[i]>>dr[i];
    ch[i]=mo[i]-'A';
    if(dr[i]=='R') d[i]=1;
    else d[i]=-1;
  }

  int ret=n;
  int l=-1,r=n;

  while(r-l>1){
    int d=(r+l)/2;
    if(left(d)) l=d;
    else r=d;
  }

  ret-=r;
  //cout<<ret<<endl;
  l=-1,r=n;

  while(r-l>1){
    int d=(r+l)/2;
    if(right(d)) r=d;
    else l=d;
  }

  ret-=n-r;

  cout<<ret<<endl;
}
