#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
#define maxn 220000
int n, ps1[maxn], ps2[maxn];
void solve() {
cin >> n;
int ans = 0;
for(int i = 1; i <= 2*n; i++) {
int x,y; cin >> x >> y;
if(y > 2) {
ans+= y-2;
y = 2;
}
if(y < 1) {
ans+= 1-y;
y = 1;
}
if(x > n) {
ans+= x-n;
x = n;
}
if(x < 1) {
ans+= 1-x;
x = 1;
}
if(y == 1)
ps1[x]++;
else
ps2[x]++;
}
for(int i = 1; i <= n; i++) {
ps1[i]+= ps1[i-1];
ps2[i]+= ps2[i-1];
ps1[i]--;
ps2[i]--;
if(ps1[i] > 0 && ps2[i] < 0) {
int ch = min(ps1[i],-ps2[i]);
ans+= ch;
ps1[i]-= ch;
ps2[i]+=ch;
}
if(ps2[i] > 0 && ps1[i] < 0) {
int ch = min(ps2[i],-ps1[i]);
ans+= ch;
ps2[i]-= ch;
ps1[i]+=ch;
}
ans+= abs(ps1[i]);
ans+= abs(ps2[i]);
}
cout << ans << endl;
}
int32_t main() {
ios::sync_with_stdio(false); cin.tie(0);
// freopen("in.in", "r", stdin);
//freopen("out.out", "w", stdout);
int tt = 1;
// cin >> tt;
while(tt--) solve();
}
