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#include<bits/stdc++.h>
using namespace std;
using LL=long long;
#define FOR(i,l,r) for(int i=(l);i<=(r);++i)
#define REP(i,n) FOR(i,0,(n)-1)
#define ssize(x) int(x.size())
template<class A,class B>auto&operator<<(ostream&o,pair<A,B>p){return o<<'('<<p.first<<", "<<p.second<<')';}
template<class T>auto operator<<(ostream&o,T x)->decltype(x.end(),o){o<<'{';int i=0;for(auto e:x)o<<(", ")+2*!i++<<e;return o<<'}';}
#ifdef DEBUG
#define debug(x...) cerr<<"["#x"]: ",[](auto...$){((cerr<<$<<"; "),...);}(x),cerr<<'\n'
#else
#define debug(...) {}
#endif

string times(LL x, const string& s) {
    if (x == 0) {
        return "";
    }
    if (x == 1) {
        return s;
    }
    if (x < 9) {
        return to_string(x) + "[" + s + "]";
    }
    assert(x >= 9);
    return "9[" + times(x / 9, s) + "]" + times(x % 9, s);
}

string solve_without_edge(LL n) {
    assert(n >= 1);
    if (n == 1) {
        return "DF";
    }
    if (n % 2 == 1 or n < 4) {
        string ret;
        ret += "D";
        ret += times(n - 1, "FD");
        ret += times(n - 1, "B");
        ret += solve_without_edge(n - 1);
        ret += "F";
        return ret;
    }
    string ret;
    ret += times(n, "D");
    ret += times(n - 1, "F");
    ret += times(n / 2 - 1, "BD");
    ret += times(n / 2 - 1, "B" + times(n / 2 - 1, "FB") + times(n / 2, "D"));
    ret += times(n - 1, "BF");
    ret += times(2, solve_without_edge(n / 2 - 1));
    ret += "DF";
    return ret;
};

string solve(LL n) {
    auto ret = solve_without_edge(n);
    ret += times(n, "B");
    return ret;
};

int main() {
	cin.tie(0)->sync_with_stdio(0);

    LL n;
    cin >> n;
    debug(n);

    auto ans = solve(n);
    cout << ans.data() << '\n';
}