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(){
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    int N,Q;
    cin>>N>>Q;
    string S;
    cin>>S;
    char t[Q],d[Q];
    int ts=-1,te=N;
    for(int i=0;i<Q;i++){
        cin>>t[i]>>d[i];
    }
    for(int i=Q-1;i>=0;i--){
        if(te-ts<=1)break;
        if(d[i]=='L'){
            if(ts<N-1 && S[ts+1]==t[i])ts++;
            if(te<N && S[te]==t[i])te++;
        }else if(d[i]=='R'){
            if(0<=ts && S[ts]==t[i])ts--;
            if(0<te && S[te-1]==t[i])te--;
        }
    }
    cout<<N-(ts+1+N-te)<<endl;
    return 0;
}
