2 set bits
else if ( j == k && i != j ) { LL x = ( 1LL << i ) + ( 1LL << j ) ; s . insert ( x ) ; } else if ( i == j && i != k ) { LL x = ( 1LL << i ) + ( 1LL << k ) ; s . insert ( x ) ; } else if ( i == k && i != j ) { LL x = ( 1LL << k ) + ( 1LL << j ) ; s . insert ( x ) ; }