// Warning 3944: (66-80): CHC: Underflow (resulting value less than 0) happens here.\nCounterexample:\nx = 0\n\n\n\nTransaction trace:\nC.constructor()
// Warning 3944: (193-207): CHC: Underflow (resulting value less than 0) happens here.\nCounterexample:\n\n\n\n\nTransaction trace:\nD.constructor()\nD.f()