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>
using namespace std;
char t[200100], d[200100];
string s;
int n, q;

char sim(int p) {
    for (int i = 0; i < q; i++) {
        if (s[p] == t[i]) p += (d[i] == 'L' ? -1 : 1);
        if (p < 0) return 'L';
        if (p >= n) return 'R';
    }
    return 0;
}

int main() {
    cin >> n >> q;
    cin >> s;
    for (int i = 0; i < q; i++) cin >> t[i] >> d[i];
    int ok, ng;
    for (ok = -1, ng = n; ng - ok > 1; ) {
        int m = (ok + ng) / 2;
        char r = sim(m);
        if (r == 'L') ok = m;
        else ng = m;
    }
    int L = ok;
    for (ok = n, ng = -1; ok - ng > 1; ) {
        int m = (ok + ng) / 2;
        char r = sim(m);
        if (r == 'R') ok = m;
        else ng = m;
    }
    int R = ok;
    cout << R - L - 1 << endl;
}
