#include <bits/stdc++.h>
using namespace std;
#define ll long long 
const ll INF = 1e18;

//
#define TIME (1.0* clock()/CLOCKS_PER_SEC)
#define file(name) if(fopen(name".inp","r")){freopen(name".inp","r",stdin); freopen(name".out","w",stdout);}
#define hackspeed ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr)
//


int main(){
	hackspeed;
	//file("");
	ll T; cin >> T;
	ll a,b,n;
	while(T--){
		cin >> a >> b >> n;
		if(a%b==0){
			cout << -1 << "\n";
		}
		else{
			ll k=(n+a-1)/a;
			ll m=k*a;	
			if(m%b==0) m+=a;
			cout << m << "\n";	
		}
		
	}
	




	//time
	cerr << "Time elapsed: " << TIME << "s.\n";
	return 0;
}