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;

int check(int n, vector<char> t, vector<char> d){
    for(int i = 0; i < Q; i++)
    {
        if(s.at(n) == t.at(i)){
            if(d.at(i) == 'L')n--;
            else n++;
        }

        if(n == -1 || n == N)return n;
    }

    return n;
}

int main() {

    cin >> N >> Q;
    cin >> s;

    vector<char> t(Q);
    vector<char> d(Q);

    for(int i = 0; i < Q; i++){
        cin >> t.at(i) >> d.at(i);
    }

    int ans1, ans2;

    int a, b;
    a = 0; b = N;

    while( b-a >= 1){
        int i = (a+b)/2;
        if(check(i, t, d) == -1)a = i+1;
        else b = i;
    }
    ans1 = a;

    a = 0; b = N;
    
    while( b-a >= 1){
        int i = (a+b)/2;
        if(check(i, t, d) == N)b = i;
        else a = i+1;
    }
    ans2 = a;

    cout <<  ans2 - ans1 << endl;
}