#pragma comment(linker, "/STACK:60777216")  

#include <cassert>
#include<iostream>
#include<algorithm>
#include<cstdio>
#include<complex>
#include<vector>
#include<cstring>
#include<set>
#include<map>
#include<cmath>
#include<queue>
#include<string>
#include<cstdlib>
#include<memory.h>
#include<ctime>
#include<bitset>
#include<fstream>
#include<queue>
#include<stack>
#include<unordered_map>
#include<unordered_set>

using namespace std;

typedef long double ld;

typedef long long ll;
typedef pair<int,int>	pii;
typedef pair<ld,ld>	pdd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef pair<ll,ll> pl;

#define FOR(i,a,b)		for(int i=(a);i<(b);i++)	
#define REP(i,n)		FOR(i,0,n)
#define SORT(v)			sort((v).begin(),(v).end())
#define UN(v)			SORT(v),(v).erase(unique((v).begin(),(v).end()),(v).end())
#define CL(a,b)			memset(a,b,sizeof a)
#define pb				push_back

ll solve(ll b, ll c,ll s,ll m){
	c-=m;
	if(c>0) return 0;
	double d = b / 2. * b / 2. - c;
	ll x = -b/2 + sqrt(d);
	x+=5;
	while(x*x+b*x+c>0) x--;
	if(x<s) return 0;
	return x-s+1;
}

int main(){	
#ifdef LocalHost
	freopen("input.txt","r",stdin);
	//freopen("output.txt","w",stdout);
#endif
#ifndef LocalHost
	freopen("sequences.in","r",stdin);
	freopen("sequences.out","w",stdout);
#endif

	int q;
	cin>>q;
	REP(Q,q){
		ll b1,b2,s1,s2,c1,c2,n;
		scanf("%lld %lld %lld %lld %lld %lld %lld",&b1,&c1,&s1,&b2,&c2,&s2,&n);
		ll t = min(c1,c2);
		c1 -= t; c2 -= t;
		ll res = 0;
		ll a = 0;
		ll b = 4e18;
		while(a<=b){
			ll m = (a+b)/2;
			//cout<<m<<endl;
			ll nm = solve(b1,c1,s1,m)+solve(b2,c2,s2,m);
			if(nm>=n)res=m,b=m-1;
			else a=m+1;
		}
		cout<<res+t<<'\n';
		//cout<<ll(1e18)<<endl;
	}

#ifdef LocalHost
	printf("TIME: %.3lf\n",ld(clock())/CLOCKS_PER_SEC);
#endif
	return 0;
}