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#include <iostream>

using namespace std;

string n2s(int64_t n){
    if (n==1) return "";
       else return to_string(n);
}

string repeat(string s,int64_t n){
    string res="";
    while (n>9){
        res+="9["+repeat(s,n/9)+"]";
        n=n%9;
    }
    if (n>0){
        if (s.size()>1 && n>1)
            res+=n2s(n)+"["+s+"]";
        else
            res+=n2s(n)+s;
    }

    return res;
}


void rysuj_R(int64_t n){
    string s="";
    s = repeat("BF",n-1)+"B" +repeat("D",n);
    cout<<repeat(s,n);

}

void rysuj_T1(){
    cout<<"B";
}


void rysuj_T2(){
    cout<<"BDBFB";
}

void rysuj_T3(){
     cout<<"BDBDBFFBDBFB";
}


void fastryga(int64_t n){
    cout<<repeat("BF",n);
    cout<<"B";
}


void fastryga2(int64_t n){
    cout<<repeat("BDBFF",n);
    cout<<"BDBFB";
}
//5[BDBFF]BDBFB


void rysuj_T(int64_t n){
    switch(n){
    case 1: rysuj_T1();
        break;
    case 2: rysuj_T2();
        break;
    case 3: rysuj_T3();
        break;
    default:
        int64_t f = 2-(n%2);
        int64_t k = (n-f)/2;

        cout<<"2[";
        rysuj_T(k);
        cout<<"]";
        cout<<repeat("D",k);
        cout<<repeat("F",k);
        cout<<repeat("D",k);
        rysuj_R(k);

        if (f==1)
            fastryga(2*k);
        else
            fastryga2(2*k);
        break;
    }
}


void rysuj_DT(int64_t n){
    rysuj_T(n);
    cout<<repeat("D",n);
    cout<<repeat("F",n);
}



int main()
{
    int64_t n;
    cin>>n;
    rysuj_DT(n);
    cout<<endl;

    return 0;
}