1872D - Plus Minus Permutation - CodeForces Solution

//							     *۝ॐ..जय श्री राम..ॐ۝
#include <bits/stdc++.h>
using namespace std;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t;
    cin >> t;
    while (t--)
    {
        long long int n, a, b;
        cin >> n >> a >> b;
        long long int lc = lcm(a, b);
        long long int a1,n1,n2;
        n1=(n/a)-(n/lc);
        n2=(n/b)-(n/lc);
        a1=(n-n1+1);
        long long int ans = (n1*(2*a1+(n1-1))/2)-(n2*(2+(n2-1))/2);
        cout<<ans<<endl;

    
    }
    return 0;
}