#include "bits/stdc++.h"
using namespace std;
int main(){
	cin.tie(NULL);
	ios_base::sync_with_stdio(0);
	int n; cin >> n;
	vector<int> nums(n);
	for (int &i : nums) cin >> i;
	int mx = *max_element(nums.begin(), nums.end());
	vector<int> cnt(mx * 2 + 1);
	for (int i : nums) cnt[i]++;
	int ans = 0;
	for (int i = 0; i * i <= mx * 2; ++i) {
		for (int j = 0; j < n; ++j) {
			cnt[nums[j]]--;
			if (nums[j] <= i * i) {
				ans += cnt[i * i - nums[j]];
			}
			cnt[nums[j]]++;
		}
	}
	cout << ans / 2 << "\n";
}

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NQoxIDIgMyA0IDU=

5
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