#include <iostream> using namespace std; int main () { int a,b,c,d; int dx,dy; cin>> a>>b>>c>>d; dx = c-a; dy = d -b ; if(dx<0) dx = -dx;//负负得正 if(dy<0) dy = -dy;//负负得正 //dx,dy肯定是正数 if(dx>dy) cout<<dx; else cout<<dy; return 0; }