include

include

include

include

include

using namespace std; struct node {

string s,t;

}; const int NR=110; node a[NR]; bool cmp(node x,node y) {

return x.t>y.t;

} int main() {

int n,i;
cin>>n;
for(i=1;i<=n;i++)
{
	cin>>a[i].s;
	if(a[i].s.size()==1) a[i].t=a[i].s+"000000000";
	if(a[i].s.size()==2) a[i].t=a[i].s+"00000000";
	if(a[i].s.size()==3) a[i].t=a[i].s+"0000000";
	if(a[i].s.size()==4) a[i].t=a[i].s+"000000";
	if(a[i].s.size()==5) a[i].t=a[i].s+"00000";
	if(a[i].s.size()==6) a[i].t=a[i].s+"0000";
	if(a[i].s.size()==7) a[i].t=a[i].s+"000";
	if(a[i].s.size()==8) a[i].t=a[i].s+"00";
	if(a[i].s.size()==9) a[i].t=a[i].s+"0";
}
sort(a+1,a+n+1,cmp);
for(i=1;i<=n;i++) cout<<a[i].s;
return 0;

}