#include <iostream>
#include <queue>
#include <vector>

std::priority_queue<int, std::vector<int>, std::greater<int>> get_nums(std::vector<int> &v){
    std::priority_queue<int, std::vector<int>, std::greater<int>> q;
    for(int i:v) {
        q.push(i);
    }
    return q;
}

int main() {
    int n = 0;
    int result = 0;
    std::vector<int> nums;
    std::cin >> n;
    for (int i = 0; i < n; ++i) {
        int a;
        std::cin >> a;
        nums.push_back(a);
    }
    std::priority_queue<int, std::vector<int>, std::greater<int>> q = get_nums(nums);
    for(int i = 0; i < n - 1; ++i) {
        int a = q.top();
        q.pop();
        int b = q.top();
        q.pop();
        q.emplace(a * b);
        result += a * b;
    }
    std::cout << result;
    return 0;
}