int main()
{
int t,i,j,k,n,s,m;
scanf("%d",&t);
pii p;
while(t--){
v.clear();
scanf("%d",&n);
for(i=0;i<n;i++){
scanf("%d %d",&j,&k);
v.push_back(ii(j,0));
v.push_back(ii(k,1));
}
sort(v.begin(),v.begin()+2*n);
s=0,m=-SENTINEL;
for(i=0;i<2*n;i++){
p=v[i];
if(p.second==0)s+=1;
else s-=1;
m=max(m,s);
}
printf("%d\n",m);
}
return 0;
}
int main()
{
sive();
int cas=0,t;
scanf("%d",&t);
while(t--)
{
scanf("%lld %lld %lld",&a,&b,&l);
v.clear();
mem(a1,0);mem(b1,0);
aprime=0;bprime=0;lprime=0;
factor(a,0);
factor(b,1);
factor(l,2);
ll ans=make();
if(ans==-1) printf("Case %d: impossible\n",++cas);
else printf("Case %d: %d\n",++cas,ans);
}
return 0;
}