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>
const int INF=1e9,MOD=1e9+7;
const long long LINF=1e18;
using namespace std;
#define int long long
//template

//main
signed main(){
  int N,Q;cin>>N>>Q;
  string s;cin>>s;
  std::vector<char> t(Q),d(Q);
  for(int i=0;i<Q;i++)cin>>t[i]>>d[i];

  int now=0;
  for(int i=Q-1;i>=0;i--){
    if(t[i]==s[now]&&d[i]=='L')now++;
    if(now==0)continue;
    if(t[i]==s[now-1]&&d[i]=='R')now--;
  }

  int now2=N-1;
  for(int i=Q-1;i>=0;i--){
    if(t[i]==s[now2]&&d[i]=='R')now2--;
    if(now2==N-1)continue;
    if(t[i]==s[now2+1]&&d[i]=='L')now2++;
  }



  cout<<max(0LL,now2-now+1)<<endl;
}
