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;

const int N = 200005;

int n, q;
char s[N];
char t[N], d[N];

int fall(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 -1;
    if (x >= n) return 1;
  }
  
  return 0;
}

int main() {
  scanf("%d %d", &n, &q);
  scanf("%s", s);
  
  for (int i=0; i<q; i++) {
    getchar();
    scanf("%c %c", t + i, d + i);
  }
  
  int l = 0, r = n-1;
  int ansL = -1;
  while (l <= r) {
    int mid = l + r >> 1;
  
    if (fall(mid) == -1) {
      ansL = mid;
      l = mid + 1;
    } else r = mid - 1;
  }
  
  int ansR = n;
  l = 0, r = n-1;
  while (l <= r) {
    int mid = l + r >> 1;
    
    if (fall(mid) == 1) {
      ansR = mid;
      r = mid - 1;
    } else l = mid + 1;
  }
  
  printf("%d\n", n - min(n, (ansL+1) + (n-ansR)));
  return 0;
}
