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
using namespace std;
signed main(){
  int N,Q;
  string S;
  cin>>N>>Q>>S;
  vector<pair<char,char>> A(Q);
  for(pair<char,char> &p:A)cin>>p.first>>p.second;
  int ok=-1,ng=N;
  while(ng-ok>1){
    int n=(ok+ng)/2,m=n;
    for(pair<char,char> p:A){
      if(S[m]==p.first){
        if(p.second=='R')m++;
        else m--;
      }
      if(m==-1){
        ok=n;
        goto home;
      }
      if(m==N){
        ng=n;
        goto home;
      }
    }
    ok=n;
    home:;
  }
  int mx=ok;
  ok=N,ng=-1;
  while(ok-ng>1){
    int n=(ok+ng)/2,m=n;
    for(pair<char,char> p:A){
      if(S[m]==p.first){
        if(p.second=='R')m++;
        else m--;
      }
      if(m==-1){
        ng=n;
        goto home2;
      }
      if(m==N){
        ok=n;
        goto home2;
      }
    }
    ok=n;
    home2:;
  }
  cout<<mx-ok+1<<endl;
}