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;

char t[200005], d[200005];
int n, q;
string s;

int check(int m) {
    for (int i = 0; i < q; i++) {
        if (s[m] == t[i]) {
            if (d[i] == 'L')
                m--;
            else
                m++;
        }
        if (m < 0)
            return 1;
        else if (m >= n)
            return 2;
    }
    return 0;
}

int main() {
    cin >> n >> q;
    cin >> s;
    for (int i = 0; i < q; i++) cin >> t[i] >> d[i];
    int l1 = -1, r1 = n;
    int l2 = -1, r2 = n;
    while (r1 - l1 > 1) {
        int mid = (l1 + r1) / 2;
        if (check(mid) == 1)
            l1 = mid;
        else
            r1 = mid;
    }
    while (r2 - l2 > 1) {
        int mid = (l2 + r2) / 2;
        if (check(mid) == 2)
            r2 = mid;
        else
            l2 = mid;
    }
    cout << max(0, l2 - r1 + 1) << endl;
    return 0;
}
