#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(auto i = (a); i < (b); i++)
#define pb push_back
#define fs first
#define sc second
typedef long long ll;
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ii> vii;
typedef vector<vii> vvii;

const double EPS = 1e-9;

int main() {
    cin.sync_with_stdio(false);
    int n;
    cin >> n;
    vii A(n);
    rep(i,0,n) cin >> A[i].fs >> A[i].sc;
    int mx_one = A[0].fs - A[0].sc;
    int mn_one = A[0].fs - A[0].sc;
    int mx_two = A[0].fs + A[0].sc;
    int mn_two = A[0].fs + A[0].sc;
    rep(i,0,n) {
        mx_one = max(mx_one, A[i].fs - A[i].sc);
        mn_one = min(mn_one, A[i].fs - A[i].sc);
        mx_two = max(mx_two, A[i].fs + A[i].sc);
        mn_two = min(mn_two, A[i].fs + A[i].sc);
    }
    if(n == 1) {
        cout << 4 << endl;
        return 0;
    }
    int cost = (mx_one - mn_one + 1) +  (mx_two - mn_two + 1) + 2;
    if(mx_one == mn_one || mx_two == mn_two) cost++;
    cout << cost << endl;
}