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>
using namespace std;
int N,Q;
string s;
vector<char> t(200009),d(200009);
int lb,ub,LB,UB;

bool C(int x){
  for(int i=0;i<Q;i++){
    if(s[x]==t[i]){
      if(d[i]=='L')x--;
      else x++;
    }
    if(x<0)return false;
    if(x>=N)return true;;
  }
  return true;
}

bool Cc(int x){
  for(int i=0;i<Q;i++){
    if(s[x]==t[i]){
      if(d[i]=='L')x--;
      else x++;
    }
    if(x>=N)return false;
    if(x<0)return true;
  }
  return true;
}

int main(){
  cin >> N >> Q >> s;
  for(int i=0;i<Q;i++)cin >> t[i] >> d[i];
  lb=-1,ub=N,LB=-1,UB=N+1;
  while(ub-lb>1){
    int mid=(ub+lb)/2;
    if(C(mid))ub=mid;
    else lb=mid;
  }
  while(UB-LB>1){
    int mid=(UB+LB)/2;
    if(Cc(mid))LB=mid;
    else UB=mid;
  }
  //cout << LB << endl;
  //cout << ub << endl;
  cout << LB-ub+1 << endl;
}