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<cmath>
#include<string>
using namespace std;

//input
int N, Q;
string s;
char t[200020];
char d[200020];

bool isOK(int idx, int dst) {
    for (int i = 0; i < Q; ++i) {
        if (s[idx] == t[i]) {
            if (d[i] == 'R') ++idx;
            else --idx;
        }
        if (idx == dst) return true;
        else if (idx == -1 || idx == N) return false; 
    }
    return false;
}

int bisection(int dst) {
    int ng = N + (-1) - dst;
    int ok = dst;

    while(abs(ok - ng) > 1) {
        int mid = (ok + ng) / 2;
        if (isOK(mid, dst)) ok = mid;
        else ng = mid;
    }
    return ok;
}

int main() {
    cin >> N >> Q;
    cin >> s;
    for (int i = 0; i < Q; ++i) cin >> t[i] >> d[i];

    int r = bisection(-1);
    int l = bisection(N);

    if (l <= r) cout << 0 << endl;
    else cout << N - (N - l) - (r + 1) << endl;

}