17:2

#include<bits/stdc++.h>
#define ll long long
ll function_value(ll a,ll b,ll c,ll x)
{
    return (a*x*x+b*x+c);
}
ll find_x(ll a,ll b,ll c,ll k)
{
    ll l=0,r=1000000,ans;
    while(l<=r)
    {
        ll mid=(l+r)/2;

        if(function_value(a,b,c,mid)<k)
        {
            l=mid+1;
        }
        else

        {
            ans=mid;
            r=mid-1;

        }
    }
    return ans;
}
using namespace std;
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        ll a,b,c,k;
        cin>>a>>b>>c>>k;
        cout<<find_x(a,b,c,k)<<"\n";
    }
}