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>

using namespace std;

int main(){
    int N, Q;
    string s;
    char t[200000];
    char d[200000];
    cin >> N >> Q;
    cin >> s;
    for(int i = 0; i < Q; i++){
        cin >> t[i] >> d[i];
    }
    int l = -1;
    int r = N;
    for(int i = Q-1; i >= 0; i--){
        if(l == -1){
            if(t[i] == s[0] && d[i] == 'L') l = 0;
        }else{
            if(t[i] == s[l] && d[i] == 'R') l--;
            if(t[i] == s[l+1] && d[i] == 'L') l++;
        }
    }
    for(int i = Q-1; i >= 0; i--){
        if(r == N){
            if(t[i] == s[N-1] && d[i] == 'R') r = N-1;
        }else{
            if(t[i] == s[r] && d[i] == 'L') r++;
            if(t[i] == s[r-1] && d[i] == 'R') r--;
        }
    }
    //cout << l << ' ' << r << endl;
    if(l >= r) cout << 0 << endl;
    else cout << r-l-1 << endl;
}