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 N,Q;
char t[200010],d[200010];
string S;

bool ok(int id){
    int now = id;
    for(int i=1;i<=Q;i++){
        if(S[now]==t[i]){
            if(d[i]=='L') now--;
            else now++;
        }
        if(now==-1 || now==N) return true;
    }
    return false;
}

int main(){
    cin >> N >> Q >> S;
    for(int i=1;i<=Q;i++){
        cin >> t[i] >> d[i];
    }
    int l1 = -1,r1 = N;
    while(l1+1<r1){
        int m = (l1+r1)/2;
        if(ok(m)) l1 = m;
        else r1 = m;
    }
    int l2 = -1,r2 = N;
    while(l2+1<r2){
        int m = (l2+r2)/2;
        if(ok(m)) r2 = m;
        else l2 = m;
    }
    if(l1>=r2) cout << 0 << endl;
    else cout << N-(l1+1)-(N-r2) << endl;
}