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 <string>

using namespace std;

int main(){
    int N,Q;
    string s;

    cin >> N >> Q >> s;    
    s="0"+s+"0";
    
    string t,d,tmp_t,tmp_d;

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

    int L=0,R=N+1;;

    for(int i=Q-1;i>-1;--i){
        if(t[i]==s[L] && d[i]=='R') L=L-1;
        else if(t[i]==s[L+1] && d[i]=='L') L=L+1;
        if(t[i]==s[R] && d[i]=='L') R=R+1;
        else if(t[i]==s[R-1] && d[i]=='R') R=R-1;
    }
    
    cout << R-L-1;

}