program sample
	implicit none
    
	character(len=*) :: O,E
    integer(8) :: x,y,i
    
    
    read(*,*) O,E
    x = len(O)
    y = len(E)
    
    	if (x == y) then
        	do i = 1,y
            	write(*,*) O(i:i),E(i:i)
            end do
        else
        	do i = 1,x
              if (i < x) then
                write(*,*) O(i:i),E(i:i)
              else 
              	write(*,*) O(i:i)
              end if
          	end do
    	end if

end program sample
