#include<bits/stdc++.h>
using namespace std;
using LL=long long;
#define FOR(i,l,r) for(int i=(l);i<=(r);++i)
#define REP(i,n) FOR(i,0,(n)-1)
#define ssize(x) int(x.size())
template<class A,class B>auto&operator<<(ostream&o,pair<A,B>p){return o<<'('<<p.first<<", "<<p.second<<')';}
template<class T>auto operator<<(ostream&o,T x)->decltype(x.end(),o){o<<'{';int i=0;for(auto e:x)o<<(", ")+2*!i++<<e;return o<<'}';}
#ifdef DEBUG
#define debug(x...) cerr<<"["#x"]: ",[](auto...$){((cerr<<$<<"; "),...)<<'\n';}(x)
#else
#define debug(...) {}
#endif
int main() {
cin.tie(0)->sync_with_stdio(0);
int n;
cin >> n;
LL odp = 0;
vector<vector<int>> t(n, vector (2, -1));
REP (i, n * 2) {
int a, b;
cin >> a >> b;
if (b > 1) {
odp += b - 2;
b = 1;
}
else {
odp += 1 - b;
b = 0;
}
if (a < 1) {
odp += 1 - a;
a = 1;
}
if (a > n) {
odp += a - n;
a = n;
}
--a;
++t[a][b];
}
int a = 0, b = 0;
REP (i, n) {
a += t[i][0];
b += t[i][1];
if (a < 0 && b > 0) {
int g = min(-a, b);
odp += g;
a += g;
b -= g;
}
if (b < 0 && a > 0) {
int g = min(a, -b);
odp += g;
a -= g;
b += g;
}
odp += abs(a) + abs(b);
}
cout << odp << endl;
}
