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 _ ios_base::sync_with_stdio(0);cin.tie(0);
#define REP(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;

char t[200010];
char d[200010];
char s[200010];
int main(){ _;
  int n,q;cin>>n>>q;
  REP(i,n) cin>>s[i+1];
  REP(i,q) cin>>t[i]>>d[i];
  s[0]=s[n+1]='_';

  int l=0,r=n+1;
  for(int i=q-1;i>=0;i--){
    if(d[i]=='L'){
      if(s[l+1]==t[i]) l++;
      if(s[r  ]==t[i]) r++;
    }else{
      if(s[r-1]==t[i]) r--;
      if(s[l  ]==t[i]) l--;
    }
    //cout<<l<<" "<<r<<endl;
  }
  cout<<r-l-1<<endl;
}
