package main import . "fmt" func main() { var a,b int Scan(&a,&b) if a>b { a,b=b,a } ok:=a*2 ng:=a+b-ok df:=ok-ng if df<0 { df=-df } for ok>=2 { ok-=2 ng+=2 x:=ok-ng if x<0 { x=-x } if x