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;
int main()
{
    int N, Q; cin >> N >> Q;
    string s; cin >> s;
    vector<char> T(Q), D(Q);
    for (int i = 0; i < Q; i++) cin >> T[i] >> D[i];
    auto simulate = [&](int x) {
        for (int i = 0; i < Q; i++) {
            if (s[x] == T[i]) {
                x += (D[i] == 'L' ? -1 : +1);
                if (x < 0) return -1;
                if (x >= N) return 1;
            }
        }
        return 0;
    };
    int A, B;
    {
        int ok = -1, ng = N;
        while (abs(ok - ng) > 1) {
            int mid = (ok + ng) / 2;
            (simulate(mid) < 0 ? ok : ng) = mid;
        }
        A = ok;
    }
    {
        int ok = -1, ng = N;
        while (abs(ok - ng) > 1) {
            int mid = (ok + ng) / 2;
            (simulate(mid) <= 0 ? ok : ng) = mid;
        }
        B = ok;
    }
    cout << (B - A) << endl;
    return 0;
}