# include<iostream> #include<cstdio> using namespace std; int main(){ int a,b,c.d; int n=0,z=0; scanf(%d%d%d%d,&a,&b,&c,&d; if(a>b){ n=a-b; }else{ n=b-a; } if(c>d){ z=c-d; }else{ z=d-c; } if(n>z){ cout<<n; }else{ cout<<z; return 0; }