program sample
    implicit none
    character(100)::s,t,ans
    integer(8) :: i,j,k,m,n
    integer(8)::a,b,c,d
    integer(8),allocatable::x(:),y(:)
  
    read(*,*) s
    read(*,*)t
    n=len_trim(s)
    m=len_trim(t)
    if(m>n)then
        write(*,*)'UNRESTORABLE'
        stop
    end if
    a=-1
    do i=n,m,-1
        do j=m,1,-1
            if(s(i-m+j:i-m+j) .ne. t(j:j) .and. s(i-m+j:i-m+j) .ne. '?')then
                exit
            elseif(j==1)then
                a=i-m
                s(i-m+1:i)=t
            end if
        end do
        if(a>=0)then
            exit
        elseif(a==-1 .and. i==m)then
            write(*,*)'UNRESTORABLE'
            stop
        end if
    end do
    do i=1,n
        if(s(i:i) .eq. '?')then
            s(i:i)='a'
        end if
    end do
    write(*,*)s
    stop
end program sample
  

