#include<bits/stdc++.h>
using namespace std;

string addtwobigintegers(string &a, string &b) {
	string ans;
	int i = a.length() - 1, j = b.length() - 1, carry = 0;
	while (i >= 0 && j >= 0) {
		int sum = (a[i] - 48 + b[j] - 48 + carry);
		int tempadd = (sum % 10); //8
		carry = (sum / 10);//9
		ans.push_back(tempadd + 48);
		i--; j--;
	}
	while (i >= 0) {
		int sum = (a[i] - 48 + carry);
		int tempadd = (sum % 10);
		carry = (sum / 10);
		ans.push_back(tempadd + 48);
		i--;
	}
	while (j >= 0) {
		int sum = b[j] - 48 + carry;
		int tempadd = (sum % 10);
		carry = (sum / 10);
		ans.push_back(tempadd + 48);
		j--;
	}

	if (carry != 0) ans.push_back(carry + 48);

	reverse(ans.begin(), ans.end());

	// for (auto &i : ans )cout << i; cout << endl;
	//how to add two big integers
	//two pointers
	//comparison
	//exhausting i or j
	//carry forwarding
	return ans;
}

int minsubsequences(vector<int>& v, int n, int k) {
	sort(v.begin(), v.end());
	int count = 1, m = v[0];
	for (int i = 0; i < n; i++) {
		//curr i will act as M
		if ((v[i] - m) <= k) continue;
		else {
			count++;
			m = v[i];
		}
	}
	return count;
}

void merge(vector<int>&v, int start, int mid, int end, int &rpcount) {
	int i = start, j = mid + 1, k;
	while (i <= mid && j <= end) {
		if (v[i] > (2 * v[j])) {
			rpcount += (mid - i + 1);
			j++;
		}
		else i++;
	}

	i = start, j = mid + 1, k = 0;
	int temp[end - start + 1];
	while (i <= mid && j <= end) {
		if (v[i] < v[j]) {
			temp[k] = v[i];
			i++; k++;
		}
		else {
			temp[k] = v[j];
			j++; k++;
		}
	}
	while (i <= mid) {
		temp[k] = v[i];
		i++; k++;
	}
	while (j <= end) {
		temp[k] = v[j];
		j++; k++;
	}
	for (int i = start; i <= end; i++) {
		v[i] = temp[i - start];
	}
}

void dividenconquer(vector<int>&v, int start, int end, int &rpcount) {
	if (start < end) {
		int mid = (start + (end - start) / 2);
		dividenconquer(v, start, mid, rpcount);
		dividenconquer(v, mid + 1, end, rpcount);
		merge(v, start, mid, end, rpcount);
	}
}
int main() {
	//43 : 11 + 11 + 11 +10
	//564 :
	//99 :
	//909 :9

	// //adding two big integers

	// int n, k; cin >> n >> k;
	// vector<int> v(n);
	// for (auto&i : v) cin >> i;
	// int ans = minsubsequences(v, n, k);
	// cout << ans << endl;

	// int n, addrocks; cin >> n >> addrocks;
	// vector<int> capacity(n), rocks(n);
	// for (auto &i : capacity) cin >> i;
	// for (auto &i : rocks) cin >> i;
	// vector<int> needed(n);
	// for (int i = 0; i < n; i++) needed[i] = (capacity[i] - rocks[i]);


	// sort(needed.begin(), needed.end());
	// int tempsum = 0, ans = 0;
	// for (int i = 0; i < n; i++) {
	// 	tempsum += needed[i];
	// 	if (tempsum <= addrocks) {
	// 		ans = (i + 1);
	// 	}
	// 	else {
	// 		break;
	// 	}
	// }
	// cout << ans << endl;



	int n; cin >> n;
	vector<int> v(n);
	for (int i = 0; i < n; i++) cin >> v[i];
	int rpcount = 0;
	dividenconquer(v, 0, n - 1, rpcount);
	cout << rpcount << endl;
	return 0;
}