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 <string>
#include <vector>
#include <algorithm>

using namespace std;

int n, q;
string s;
vector<vector<char>> ope;

bool IsOK(bool first, int index) {
    for (int i = 0; i < q; i++) {
        if (s[index] == ope[i][0]) index += ope[i][1] == 'L' ? -1 : 1;
        if (index < 0 || n <= index)break;
    }
    if (first)return index >= 0;
    return index < n;
}

int Bin(bool first) {
    int ng = first ? -1 : n;
    int ok = first ? n : -1;

    while (abs(ok - ng) > 1) {
        int mid = ng + (ok - ng) / 2;

        if (IsOK(first, mid)) ok = mid;
        else ng = mid;
    }

    return ok;
}

int main() {
    cin >> n >> q >> s;

    ope = vector<vector<char>>(q, vector<char>(2));
    for (int i = 0; i < q; i++)cin >> ope[i][0] >> ope[i][1];

    cout << Bin(false) - Bin(true) + 1 << endl;
    return 0;
}