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 <algorithm>
#include <string>
using namespace std;
 
int main()
{
    int n, q;
    cin >> n >> q;
    string s;
    cin >> s;
    s.insert(s.begin(), '?');
    s.push_back('?');
    char t[200006], d[200006];
    for(int i = 1; i <= q; i++){
        cin >> t[i] >> d[i];
    }
    int nr = n + 1;
    int nl = 0;
    for(int i = q; i > 0; i--){
        if(nr - nl == 1){
            cout << 0 << endl;
            return 0;
        }
        if(d[i] == 'R'){
            if(t[i] == s[nr - 1]){
                nr--;
            }
            if(t[i] == s[nl]){
                nl--;
            }
        }
        if(d[i] == 'L'){
            if(t[i] == s[nr]){
                nr++;
            }
            if(t[i] == s[nl + 1]){
                nl++;
            }
        }
    }
    cout << n - nl - (n - nr + 1) << endl;
}