#include<iostream> using namespace std; int main() { int a,b,c,d; cin>>a>>b>>c>>d; if((a>c&&d)||(b>c&&d)) { if((a-c>b-c)&&(a-c>b-d)||(a-d>b-c)&&(a-d>b-d)) } { if(a-c>a-d) { cout<<a-c; } else { cout<<a-d; } } else { if(b-c>b-d) { cout<<b-c; } else { cout<<b-d; } else { if((c-a>c-b)&&(c-a>d-b)||(d-b>c-b)&&(d-a>d-b)) } { if(c-a>d-a) { cout<<c-a; } else { cout<<d-a; } } else { if(c-b>d-b) { cout<<c-b; } else { cout<<d-b; } } }