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>
typedef long long ll;
using namespace std;

int main() {
  int n,q;
  cin>>n>>q;
  string s;
  cin>>s;
  char t[200005],d[200005];
  for (int i=0; i<q; i++) {
    cin>>t[i]>>d[i];
  }

  int mid,lo=-1,hi=n,left,right;
  while (hi-lo>1) {
    mid=(lo+hi)/2;
    int pos=mid;
    for (int i=0; i<q; i++) {
      if (s[pos]==t[i]) {
	if (d[i]=='L') pos--;
	else pos++;
	if (pos<0||pos>=n) break;
      }
    }
    if (pos<0) lo=mid;
    else hi=mid;
  }
  left=hi;
  
  lo=-1;
  hi=n;
  while (hi-lo>1) {
    mid=(lo+hi)/2;
    int pos=mid;
    for (int i=0; i<q; i++) {
      if (s[pos]==t[i]) {
	if (d[i]=='L') pos--;
	else pos++;
	if (pos<0||pos>=n) break;
      }
    }
    if (pos>=n) hi=mid;
    else lo=mid;
  }
  right=lo;
  
  cout<<max(0,right-left+1)<<endl;
  return 0;
}