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;

#define all(x) (x).begin(),(x).end()
#define SP <<" "<<
#define MOD 1000000007
#define IINF 1000000000
#define LINF 1000000000000000000

typedef long long LL;
typedef long double LD;

int main(){
  int n,q;
  cin >> n >> q;
  string s;
  cin >> s;
  vector<pair<char,char>> td(q);
  for(int i=0;i<q;i++){
    cin >> td[i].first >> td[i].second;
  }
  reverse(all(td));
  int l=0,r=n;
  for(int i=0;i<q;i++){
    if(td[i].second=='L'){
      if(s[l]==td[i].first) l++;
      if(r<n) if(s[r]==td[i].first) r++;
    }else{
      if(l>0) if(s[l-1]==td[i].first) l--;
      if(s[r-1]==td[i].first) r--;
    }
  }
  cout << r-l << endl;
  return 0;
}
