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<vector>
using namespace std;
bool solve(string s,vector<pair<char,char>>q,int p,int n){
  for(int i=0;i<q.size()&&p!=n;i++)if(q[i].first==s[p])p+=(q[i].second=='R'?1:-1);
  return p==n?true:false;
}
int main(){
  int n,q,ok,ng,ans;
  cin>>n>>q;
  ans=n;
  string s;
  cin>>s;
  s="0"+s+"0";

  vector<pair<char,char>>Q(q);
  for(int i=0;i<q;i++)cin>>Q[i].first>>Q[i].second;

  ok=1,ng=n+1;
  while(abs(ok-ng)>1){
    int mid=(ok+ng)/2;
    if(solve(s,Q,mid,0))ok=mid;
    else ng=mid;
  }
  ans-=ok;

  ok=n+1,ng=1;
  while(abs(ok-ng)>1){
    int mid=(ok+ng)/2;
    if(solve(s,Q,mid,n+1))ok=mid;
    else ng=mid;
  }
  ans-=(n-ok+1);

  cout<<ans<<endl;
  return 0;
}