program main
    implicit none
    INTEGER(8) n,a(3),i,x(2),x2(2),ans(100000),flag
    CHARACTER s1*2,s2*2
    read(*,*) n,(a(i),i=1,3)
    flag=1
!0が二つ含まれる/A+B+C=2の場合
    if ( ((a(1)==0 .and. a(2)==0) .or. (a(2)==0 .and. a(3)==0) .or. (a(3)==0 .and. a(1)==0)) .and. a(1)+a(2)+a(3)/=2 ) then
        do i = 1,n
            call read_s(s1,x)
            if ( a(x(1))+a(x(2))==0 ) then
                write(*,*) "No"
                flag=0
                exit
            else
                call nomal(a,ans,x,i)
            end if
        end do
    else if ( ((a(1)==0 .and. a(2)==0) .or. (a(2)==0 .and. a(3)==0) .or. (a(3)==0 .and. a(1)==0)) .and. a(1)+a(2)+a(3)==2 ) then
        do i = 1,n
            if ( i==1 ) then
               call read_s(s1,x) 
            end if
            if ( a(x(1))+a(x(2))==0 ) then
                write(*,*) "No"
                flag=0
                exit
            else
                if ( i<n ) then
                    call read_s(s2,x2)
                end if
                call exceptional(a,ans,x,x2,i)
                x=x2
            end if
        end do
!A+B+C=2の場合
    else if ( a(1)+a(2)+a(3)==2 ) then
        call read_s(s1,x)
        do i = 1, n
            if ( i<n ) then
                call read_s(s2,x2)
            end if
            call exceptional(a,ans,x,x2,i)
            x=x2
        end do
!それ以外
    else
        do i = 1, n
            call read_s(s1,x)
            call nomal(a,ans,x,i)
        end do
    end if
!答え出力
    if ( flag==1 ) then
        write(*,*) "Yes"
        do i = 1, n
            if(ans(i)==1) then
                write(*,*) "A"
            else if ( ans(i)==2 ) then
                write(*,*) "B"
            else
                write(*,*) "C"
            end if
        end do
    end if
contains
    subroutine read_s(sr, xr)
        implicit none
        INTEGER(8),INTENT(OUT):: xr(2)
        CHARACTER(*) sr
        read(*,*) sr
        if ( sr=="AB" ) then
            xr(1)=1
            xr(2)=2
        else if ( sr=="BC" ) then
            xr(1)=2
            xr(2)=3
        else 
            xr(1)=3
            xr(2)=1
        end if
    end subroutine read_s

    subroutine nomal(an, ansn, xn,in)
        implicit none
        INTEGER(8) an(3),xn(2),ansn(100000),in
        if ( an(xn(1))>=an(xn(2)) ) then
            an(xn(1))=an(xn(1))-1
            an(xn(2))=an(xn(2))+1
            ansn(in)=xn(2)
        else
            an(xn(1))=an(xn(1))+1
            an(xn(2))=an(xn(2))-1
            ansn(in)=xn(1)
        end if
    end subroutine nomal

    subroutine exceptional(ae, anse, xe, x2e,ie)
        implicit none
        INTEGER(8) ae(3),xe(2),x2e(2),anse(100000),ie
        if ( ae(xe(1))>ae(xe(2)) ) then
            ae(xe(1))=ae(xe(1))-1
            ae(xe(2))=ae(xe(2))+1
            anse(ie)=xe(2)
        else if ( a(x(1))<a(x(2)) ) then
            ae(xe(1))=ae(xe(1))+1
            ae(xe(2))=ae(xe(2))-1
            anse(ie)=xe(1)           
        else if ( xe(1)==x2e(1) .or. xe(1)==x2e(2) ) then
            ae(xe(1))=ae(xe(1))+1
            ae(xe(2))=ae(xe(2))-1
            anse(ie)=xe(1) 
        else
            ae(xe(1))=ae(xe(1))-1
            ae(xe(2))=ae(xe(2))+1
            anse(ie)=xe(2)
        end if
    end subroutine exceptional
end program main


Measured memory_bytes: 3648