#include <iostream> using namespace std; int main(){ int x,y,fx,fy; cin>>x>>y>>fx>>fy; int a,b; a = fx - x; b = fy - y; if (a < 0){ a = a * -1; } if (b < 0){ b = b * -1; } if (a < b){ int temp = a; a = b; b = temp; } if (a < 0){ a = a * -1; } cout<<a; return 0; }