#include <bits/stdc++.h>
using namespace std;
#define ALL(a) (a).begin(),(a).end()
#define rALL(a) (a).rbegin(),(a).rend()
typedef pair<int, int> Pint;
typedef pair<int64_t, int64_t> Pll;
typedef int64_t ll;

int main() {
    int a, b, c, d;
    cin >> a >> b >> a >> b >> c >> d;
    cout << abs(a - c) + abs(b - d) << endl;
}