REXX DO Loop

Processing can be controlled in a DO loop in a number of ways:
ITERATE :Stops processing in a loop and returns to the start of the loop and
continues with the next item in the loop.
LEAVE :Stops processing the DO loop, and continues processing with the
next instruction after the loop.
LEAVE label :Stops processing a DO loop inside another DO loop returning
processing to DO loop with 'label' as the counter

                                                                             
E.g          DO O = 1 to 10                                                
              DO n = 1 to 10                                                
                 DO m = 1 to 10                                              
                    if m = 2 then ITERATE     /* go back to m */        
                    if m = 5 then LEAVE       /* go back to n */            
                    if m = 7 then LEAVE O     /* go back to O */          
                 end                                                        
              end                                                           
            end