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 rep(i,a,b) for(int i=int(a);i<int(b);++i)
#define SIZE 200005
#define INF 1000000005LL
#define MOD 1000000007

using namespace std;
typedef long long int ll;
typedef pair <int,int> P;

int N,Q;
string s;
char t[SIZE],d[SIZE];
int a,b;

int main(){
  cin >> N >> Q;
  cin >> s;
  rep(i,0,Q) cin >> t[i] >> d[i];
  int l = 0,r = N;
  while(r-l>1){
    int m = (l+r)/2;
    int p = m;
    rep(i,0,Q){
      if(t[i] == s[p]){
        if(d[i] == 'L') p--;
        else p++;
      }
      if(p < 0 || p >= N)break;
    }
    if(p >= 0)r = m;
    else l = m;
  }
  a = l;
  l = 0,r = N;
  while(r-l>1){
    int m = (l+r)/2;
    int p = m;
    rep(i,0,Q){
      if(t[i] == s[p]){
        if(d[i] == 'L') p--;
        else p++;
      }
      if(p < 0 || p >= N)break;
    }
    if(p < N)l = m;
    else r = m;
  }
  b = l;
  cout << b-a << endl;
  return 0;
}
