#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using vl = vector<ll>;
#define rep(i,n) for(int i=0;i<(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define fore(i_in,a) for (auto& i_in: a)
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define fio() cin.tie(nullptr);ios::sync_with_stdio(false);
#define DEBUG_CTN(v) cerr<<#v<<":";for(auto itr=v.begin();itr!=v.end();itr++) cerr<<" "<<*itr; cerr<<endl
template<class T> bool chmax(T &a, const T &b) {if (a<b) { a = b; return true; } return 0;}
template<class T> bool chmin(T &a, const T &b) {if (a>b) { a = b; return true; } return 0;}
template<class T> void print(const T &t) { cout << t << "\n"; }
const ll INF = 1LL << 62;
const int iINF = 1 << 30;

string s;

int main() {
    fio(); cin>>s;
    auto itr = s.find('.');
    print(s.substr(0,itr));
}

#include <iostream>
#include <vector>
#include <numeric>
using namespace std;
typedef long long ll;

vector<ll> v;

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);

	int n; cin >> n; v.resize(n);
	for (auto& x : v) { cin >> x; }

	ll res = 0; for (auto& x : v)
		res += x * x * (n - 1);

	ll s = accumulate(v.begin(), v.end(), 0ll);
	for (auto& x : v) res -= x * (s - x);
	cout << res << '\n'; cin.ignore(2); return 0;
}