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 <iostream>
#include <string>
#define repi(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,a) repi(i,0,a)
#define all(a) (a).begin(), (a).end()

int N, Q;
std::string s;
std::string t[200010], d[200010];
int ans;

bool C1( int x )
{
  rep( q, Q )
  {
    if( s[x] == t[q][0] )
      x += (d[q][0]=='L'?-1:1);

    if( x < 0 )
      return false;
  }

  return true;
}

bool C2( int x )
{
  rep( q, Q )
  {
    if( s[x] == t[q][0] )
      x += (d[q][0]=='L'?-1:1);

    if( x >= N )
      return false;
  }

  return true;
}

int main()
{
  std::cin >> N >> Q >> s;

  rep( i, Q )
    std::cin >> t[i] >> d[i];

  int lb = -1, ub = N;

  while( ub-lb > 1 )
  {
    int mid = (lb+ub)/2;

    (C1(mid)?ub:lb) = mid;
  }

  ans += ub;

  lb = -1, ub = N;

  while( ub-lb > 1 )
  {
    int mid = (lb+ub)/2;

    (C2(mid)?lb:ub) = mid;
  }

  ans += N-ub;

  printf( "%d\n", N-ans );

  return 0;
}