传送
#include<iostream>
using namespace std;
int main()
{
int a, b, c, d;
cin >> a >> b >> c >> d;
if(d < c)swap(d, c);
if(a > b)swap(a,b);
int len = 0;
if(c < a)
{
len = min(a - c, d - a);
}
else len = abs(c - a);
len += abs(b - d);
len = min(len, abs(b - a));
cout << len << endl;
return 0;
}
