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 <vector>
#include <string>
#include <math.h>
using namespace std;
typedef long long ll;

int main(void){
    int n, q;
    char s[200020], t[200020], d[200020];
    cin >> n >> q;
    cin >> s;
    for (int i = 0; i < q; i++) cin >> t[i] >> d[i];
    
    vector<int> a(n, 0), b(n, 0);
    int x = 0, y = n - 1, xt = 0, yt = 0;
    for (int i = q - 1; i >= 0; i--) {
        if (d[i] == 'L' && s[x] == t[i]) x++;
        if (d[i] == 'R' && x != 0 && s[x - 1] == t[i]) x--;
    }
    for (int i = q - 1; i >= 0; i--) {
        if (d[i] == 'R' && s[y] == t[i]) y--;
        if (d[i] == 'L' && y + 1 != n && s[y + 1] == t[i]) y++;
    }
    
    cout << n - x - (n - 1 - y) << endl;
    
}
