text: If no answer found return - 1
code: int ans = - 1 ; while ( start <= end ) { int mid = ( start + end ) / 2 ; int value = C * mid ; int divC = mid - 1 ; int divB = ( value % B == 0 ) ? value / B - 1 : value / B ; int divA = ( value % A == 0 ) ? value / A - 1 : value / A ; int divAB = ( value % lcm ( A , B ) == 0 ) ? value / lcm ( A , B ) - 1 : value / lcm ( A , B ) ; int divBC = ( value % lcm ( C , B ) == 0 ) ? value / lcm ( C , B ) - 1 : value / lcm ( C , B ) ; int divAC = ( value % lcm ( A , C ) == 0 ) ? value / lcm ( A , C ) - 1 : value / lcm ( A , C ) ; int divABC = ( value % lcm ( A , lcm ( B , C ) ) == 0 ) ? value / lcm ( A , lcm ( B , C ) ) - 1 : value / lcm ( A , lcm ( B , C ) ) ;