#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,sse,sse2")
#include<bits/stdc++.h>
#define int long long
///#define ll long long
#define down cout<<'\n';
#define NHP ios_base::sync_with_stdio(0);cout.tie(0);cin.tie(0);
#define modwwe int t;cin>>t; while(t--)
#define bit(i,j) (i>>j&1)
#define sobit(a) __builtin_popcountll(a)
#define task "test"
#define fin(x) freopen(x".inp","r",stdin)
#define fou(x) freopen(x".out","w",stdout)
#define pb push_back
#define checktime cerr << (double)clock() / CLOCKS_PER_SEC * 1000 << " ms";
using namespace std;
void phongbeo();
const int mod2=998244353;
const int mod1=998244353;
struct icd
{
int a,b;
};
struct ib
{
int a;
int b;
};
struct ic
{
int a,b,c;
};
struct id
{
int a,b,c,d;
};
struct ie
{
int a,b,c, d,e,f;
};
int n,m,s1,s2,s4,s3,sf,k,r,mid,s5,s6,mx,s7,s8,s9,mx2,res,dem2=0,dem=0,l;
int i,s10,s12;
int el=29;
main()
{
#ifndef ONLINE_JUDGE
///fin(task),fou(task);
#endif
NHP
/// cin>>s1;
/// modwwe
phongbeo();
}
int c[100001][2];
int b[2];
void phongbeo()
{
cin>>n;
for(int i=1;i<=n*2;i++)
{
cin>>l>>r;
if(l>=n) s2+=l-n,l=n;
if(l<=1) s2+=1-l,l=1;
if(r<=1) s2+=1-r,r=1;
if(r>=2) s2+=r-2,r=2;
c[l][r-1]++;
}
for(int i=1;i<=n;i++)
{
b[0]+=c[i][0]-1;
b[1]+=c[i][1]-1;
if(b[0]>0&&b[1]<0)
{
s3=min(abs(b[0]),abs(b[1]));
b[0]-=s3;
b[1]+=s3;
s2+=s3;
}
if(b[1]>0&&b[0]<0)
{
s3=min(abs(b[0]),abs(b[1]));
b[1]-=s3;
b[0]+=s3;
s2+=s3;
}
s2+=abs(b[0])+abs(b[1]);
}
cout<<s2;
}
