Sergey Alt@x_curveball_xRussiaFollow BadgesProblem SolvingJavaDays of JS CertificationsCertificate: Problem Solving (Basic)VerifiedskillCertificate: Problem Solving (Intermediate)VerifiedskillCertificate: Problem Solving (Advanced)VerifiedskillWork Experiencex_curveball_x has not updated employment details yet.Educationx_curveball_x has not updated education details yet.