#include<iostream>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;

class Key
{
  public:
  int _left;
  int _right;
  int _key;

  Key(int x=0,int y=0,int z=0)
  :_left(x),
  _right(y),
  _key(z)
  {}

};

function<bool(Key,Key)> func= [](Key x, Key y)
 {
     if(x._key<y._key)
     return true;
     else if(x._key==y._key)
     return x._left<=y._left;
     else
       return false;
 };


long long merge(vector<Key>& x)
{
    vector<Key>arr;
    long long number=0;
    int key=x.begin()->_key;
    int left=x.begin()->_left;
    int right=x.begin()->_right;
    for(auto&y:x)
    {
        if(y._key==key && right>=y._left)
        {
            right=max(right,y._right);
        }
        else
        {
         number+=right-left+1;
         arr.push_back({left,right,key});
           key=y._key;
           left=y._left;
           right=y._right;
        }
    }
     number+=right-left+1;
         arr.push_back({left,right,key});
    x=arr;
    return number;
}

int main()
{
    int n;cin>>n;
    vector<Key> row,column;
    for(int i=1;i<=n;++i)
    {
        int x1,y1,x2,y2;
        scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
        if(x1==x2)
        {
            if(y1<=y2)
          row.push_back({y1,y2,x1});  
          else
          row.push_back({y2,y1,x1});  
        }
        else
        {
            if(x1<=x2)
            column.push_back({x1,x2,y1});
            else
            column.push_back({x2,x1,y1});
        }
    }

    sort(row.begin(),row.end(),func);
    sort(column.begin(),column.end(),func);
   long long number=0;
   number+=merge(row);
    number+=merge(column);

    for(auto&x:row)
    for(auto&y:column)
    {
    if(  x._key>=y._left  &&  x._key<=y._right &&  y._key>=x._left  &&  y._key<=x._right)
    number--;
    }

    cout<<number;

    return 0;
}