#include <iostream> #include <cstdio> #include <iomanip> #include <cmath> using namespace std; int main(){ int x1,y1,x2,y2; cin>>x1>>y1>>x2>>y2; if(abs(x1-x2)>abs(y1-y2)) cout<<abs(x1-x2) else cout<<abs(y1-y2); }