#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int x1,x2,y1,y2; cin>>x1>>x2>>y1>>y2; int h1=abs (x1-x2) if(h1>h2){ cout<<h1; } else{ cout<<h2; } return 0; }