#include <bits/stdc++.h>
#define upmin(a,b) (a)=min((a),(b))
#define INFLL (0x3f3f3f3f3f3f3f3fll)
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int MAXN = 100055;
int A[MAXN][2];
ll Ans;
int N;
int main() {
ios::sync_with_stdio(false);
cin >> N;
for(int i = N<<1, x, y; i--;) {
cin >> x >> y;
if(x < 1) {
Ans += 1-x;
x = 1;
}
if(N < x) {
Ans += x-N;
x = N;
}
if(2 < y) {
Ans += y-2;
y = 2;
}
if(y < 1) {
Ans += 1-y;
y = 1;
}
A[x][y-1]++;
}
for(int i = 1; i <= N; i++) {
A[i][0]--; A[i][1]--;
}
for(int i = 1; i < N; i++) {
if(0 <= A[i][0] && 0 <= A[i][1]) {
Ans += A[i][0] + A[i][1];
} else if(A[i][0] <= 0 && A[i][1] <= 0) {
Ans -= A[i][0] + A[i][1];
} else if(abs(A[i][0]) < abs(A[i][1])) {
Ans += abs(A[i][0]);
A[i][1] += A[i][0];
A[i][0] = 0;
Ans += abs(A[i][1]);
} else {
Ans += abs(A[i][1]);
A[i][0] += A[i][1];
A[i][1] = 0;
Ans += abs(A[i][0]);
}
A[i+1][0] += A[i][0];
A[i+1][1] += A[i][1];
}
Ans += abs(A[N][0]);
cout << Ans << endl;
return 0;
}
