/***IN THE NAME OF ALMIGHTY ALLAH***/
/***ALHAMDULILLAH***/
 
/***From dust I have come, dust I will be***/
#include <bits/stdc++.h>
using namespace std;
#define optimize()           \
    ios::sync_with_stdio(0); \
    cin.tie(0);
#define start \
    int T;    \
    cin >> T; \
    while (T--)
#define endl '\n'
#define pb push_back
#define ll long long
#define Yes cout << "Yes\n"
#define YES cout << "YES\n"
#define No cout << "No\n"
#define NO cout << "NO\n"
 
int main()
{
    start
    {
        ll x;
        cin >> x;
        x--;
        ll res = (x*(x+1))/2;
        cout << res << endl;
    }
 
    return 0;
}