C++ :

#include <bits/stdc++.h>
using namespace std;
int main()
{
	int n;
	//freopen("F:\\QQDownlaod\\Laputa\\2015.3.23\\1(2)\\test.in","r",stdin);
	while(~scanf("%d",&n)){
		long long d[405],b[405];
		for (int i=0;i<n;i++) scanf("%lld",&d[i]);
		for (int i=0;i<n;i++) scanf("%lld",&b[i]);
		sort(d,d+n);
		sort(b,b+n);
		long long sum=0;
		for (int i=0;i<n;i++){
			sum+=(d[i]*b[n-1-i]);
		}
		printf("%lld\n",sum);
	}
	return 0;
}