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;
typedef long long ll;
#define rep(i,j,n) for (int i = j; i < (n); i++)
#define CLR(mat) memset(mat, 0, sizeof(mat))
#define out(ans) cout << ans << endl
typedef pair<int,int>P;
const ll mod=1e9+7;

int n,q;
string s;
char t[200010],d[200010];

int simu(int k){

  rep(i,0,q){
    if(s[k]!=t[i])continue;

    if(d[i]=='L')k--;
    else k++;

    if(k<0)return -1;
    if(k>=s.size())return 1;
  }
  return 0;
}

int main(){

  cin>>n>>q;
  cin>>s;
  int sn=s.size();
  rep(i,0,q)cin>>t[i]>>d[i];

  int l=-1,r=n;
  while(r-l>1){
    int mid=(l+r)/2;
    if(simu(mid)==-1)l=mid;
    else r=mid;
  }
  int L=r;

  l=-1,r=n;
  while(r-l>1){
    int mid=(l+r)/2;
    if(simu(mid)==1)r=mid;
    else l=mid;
  }
  int R=n-1-l;

  out(n-(R+L));

  return 0;
}
