#include <bits/stdc++.h>
using namespace std;
const long long INF = 1LL * 1e18;
int A[100009], B[100009];
inline int d(int a, int b, int c, int d) {
return max(a - c, c - a) + max(b - d, d - b);
}
int main() {
long long s = 0;
int N; scanf("%d",&N);
for(int i=0; i<2*N; i++) {
int X, Y; scanf("%d%d",&X,&Y);
if(Y <= 1) {
if(Y == 1 && 1 <= X && X <= N) ++A[X];
else if(X <= 1) ++A[1], s += d(1, 1, X, Y);
else if(N <= X) ++A[N], s += d(N, 1, X, Y);
else ++A[X], s += d(X, 1, X, Y);
}
else {
if(Y == 2 && 1 <= X && X <= N) ++B[X];
else if(X <= 1) ++B[1], s += d(1, 2, X, Y);
else if(N <= X) ++B[N], s += d(N, 2, X, Y);
else ++B[X], s += d(X, 2, X, Y);
}
}
for(int i=1; i<=N; i++) --A[i], --B[i];
for(int i=1; i<=N; i++) {
if(A[i] >= 0 && B[i] >= 0) s += A[i] + B[i];
else if(A[i] <= 0 && B[i] <= 0) s += - A[i] - B[i];
else {
int tmp = min(max(A[i], -A[i]), max(B[i], -B[i]));
s += tmp;
if(A[i] < 0) A[i] += tmp, B[i] -= tmp, s += - A[i] + B[i];
else A[i] -= tmp, B[i] += tmp, s += A[i] - B[i];
}
A[i+1] += A[i];
B[i+1] += B[i];
}
printf("%lld", s);
return 0;
}
