#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
const int maxn = 100000 + 10;
const int inf = 1e9;
int dw[maxn], up[maxn];
int main(){
ios_base::sync_with_stdio(false);
int n;
cin >> n;
ll answer = 0;
for (int i = 1; i <= 2*n; i++){
int x, y;
cin >> x >> y;
if (x < 1)
answer += (1 - x), x = 1;
if (n < x)
answer += (x - n), x = n;
if (y < 1)
answer += (1 - y), y = 1;
if (2 < y)
answer += (y - 2), y = 2;
if (y == 1)
dw[x] ++;
else
up[x] ++;
}
int lo = 1, hi = 1;
for (int i = 1; i <= n; i++){
while (lo <= i and dw[i] > 0){
dw[i] --;
answer += (i - lo);
lo ++;
}
while (hi <= i and up[i] > 0){
up[i] --;
answer += (i - hi);
hi ++;
}
while (hi <= i and dw[i] > 0){
dw[i] --;
answer += (i - hi + 1);
hi ++;
}
while (lo <= i and up[i] > 0){
up[i] --;
answer += (i - lo + 1);
lo ++;
}
answer += up[i] + dw[i];
up[i + 1] += up[i];
dw[i + 1] += dw[i];
}
cout << answer << endl;
}
