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 N,Q;
string S;
vector<char> t,d;

int C(int n) {
    for(int i=0; i<Q; ++i) {
        if(t[i] == S[n]) n += (d[i] == 'R' ? 1 : -1);
    }

    if(n == 0) return -1;
    else if(n == N + 1) return 1;
    else return 0;
}

int solveL() {
    int l = 0, r = N + 1;
    while(r - l > 1) {
        int m = (l + r) / 2;
        if(C(m) == -1) l = m;
        else r = m;
    }
    return l;
}

int solveR() {
    int l = 0, r = N + 1;
    while(r - l > 1) {
        int m = (l + r) / 2;
        if(C(m) == 1) r = m;
        else l = m;
    }
    return r;
}

int main() {
    cin >> N >> Q;
    cin >> S;
    S = '!' + S;
    S += '!';
    t.resize(Q);
    d.resize(Q);
    for(int i=0; i<Q; ++i) cin >> t[i] >> d[i];

    int left = solveL();
    int right = solveR();
    cout << right - 1 - left << endl;
}