F

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

#define ll     long long
#define ff     first
#define ss     second
#define pb     push_back

int main()
{
    int test;
    cin>>test;

    while(test--){
        ll a,b,c;
        cin>>a>>b>>c;

        if(a+1!=c)
        {
            cout<<-1<<endl;
            continue;
        }

        int h=log2(c*2-1);

        ll d=1<<h;
        d-=c;
        b=max(b-d,0ll);
        h+=(b+c-1)/c;

        cout<<h<<endl;
    }
}