insert  3       32       34    Tel_Aviv
 insert 4       48     11       Munich
insert  5  48  2  Paris   
insert  6   57     2  Aberdeen 
              insert     0  40 73 New_York 
insert  1  38  77  Washington   
insert   2      37  80    Blacksburg  
                    print                
 insert  1  51  0  London
print 1
 remove 3 
remove  4
remove    5  
 print 3    
 print  4
 print  5
             remove 20 
remove  -3
print -8 
insert -3    37  23  Athens
insert 3    35  139  Tokyo   
print -3 
print