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;
using ll = long long;
#define ALL(v) (v).begin(), (v).end()

int N, Q;
string s;
vector<char> t, d;

int sim(int x) {
  for (int i = 0; i < Q; ++i) {
    if (s[x] == t[i]) {
      if (d[i] == 'L') x--;
      else x++;
    }

    // マス１から落ちるとき
    if (x < 0) return -1;

    // マスNから落ちるとき
    else if (x > N-1) return -2;
  }

  return 0;
}

int main()
{
  cin >> N >> Q;
  cin >> s;
  t.resize(Q), d.resize(Q);

  for (int i = 0; i < Q; ++i) cin >> t[i] >> d[i];

  int le=-1, ri=N, mid;
  while (ri-le>1) {
    mid = (le+ri)/2;
    if (sim(mid) == -1) le = mid;
    else ri = mid;
  }

  int lle=-1, rri=N;
  while (rri-lle>1) {
    mid = (lle+rri)/2;
    if (sim(mid) == -2) rri = mid;
    else lle = mid;
  }

  cout << lle - ri + 1 << endl;
}