#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>

using namespace std;

inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v;}
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str();}

typedef vector<int> vi;
typedef vector<vi>  vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;

#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EACH(t,i,c) for(t::iretator i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

const double EPS = 1e-10;

int main() {
	int n;
	cin >> n;
	vvi cost(n, vi(2));

	REP(i, n) {
		cin >> cost[i][0] >> cost[i][1];
	}

	ll num = 0;
	int max00, max11;
	int max01, max10;
	int p0, p1;

	REP(i, n-1) {
		max00 = max11 = max01 = max10 = 1;
		REP(j, n) {
			if(cost[j][0] >= max00) {
				max00 = cost[j][0];
				max01 = cost[j][1];
				p0 = j;
			}
		}

		REP(j, n) {
			if(cost[j][1] >= max11 && p0 != j) {
				max10 = cost[j][0];
				max11 = cost[j][1];
				p1 = j;
			}
		}

		cost[p0][0] = cost[p1][0]; 
		cost[p1][0] = cost[p1][1] = 0;
		p0 = p1;

		num += max00*max01*max10*max11;
	}

	cout << num << endl;
}