#include <iostream> using namespace std; void hsg(int n,char a,char b,char c) { if(n==1){ cout<<a<<":"<<"->"<<c<<endl; return; } hsg(n-1,a,c,b); hsg(1,a,b,c); hsg(n-1,b,a,c); } int main() { int n; cin>>n; hsg(n,'A','B','C'); return 0; }