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 <algorithm>
#include <string>
#include <vector>
#include <cmath>
#include <map>
#include <queue>
#include <iomanip>
#define MOD 1000000007
typedef long long ll;
using namespace std;

int N,Q;
string s;
char t[200020],d[200020];

bool judge(int mid,int x){
  int now=mid-1;
  for(int i=0;i<Q;i++){
    if(s[now]==t[i]){
      if(d[i]=='L') now=now-1;
      else now=now+1;
    }
    if(now==x) return true;
    else if(x==N&&now==-1) return false;
    else if(x==-1&&now==N) return false;
  }
  return false;
}

int main(){
  cin>>N>>Q;
  cin>>s;
  for(int i=0;i<Q;i++){
    cin>>t[i]>>d[i];
  }

  int ok=0,ng=N+1;
  while(ng-ok>1){
    int mid=(ok+ng)/2;
    if(judge(mid,-1)) ok=mid;
    else ng=mid;
  }
  int ans=ok;

  ok=N+1;
  ng=0;
  while(ok-ng>1){
    int mid=(ok+ng)/2;
    if(judge(mid,N)) ok=mid;
    else ng=mid;
  }

  cout<<N-min(ans+N-ok+1,N)<<endl;

  return 0;
}
