program main
    implicit none
    character(50)::o,e
    character(100)::ans
    integer::on,en,i
    read(*,*) o
    read(*,*) e
    
    on=len(o)
    en=len(e)
    
    if (on==en)then
        do i=1,on
            ans=ans//o(i:i)
            ans=ans//e(i:i)
        end do
    else
        ans=ans//o(1:1)
        do i=1,en
            ans=ans//e(i:i)
            ans=ans//o(i:i)
        end do
    end if
    
    write(*,*) ans(1:on+en)
    
    stop
end program main
    