program aaa
implicit none

integer :: one, two, three, four
integer :: a, b, c
character(4) :: s

read*, s

one=iachar(s(1:1))  + 1000
two=iachar(s(2:2))  + 1000
three=iachar(s(3:3))+ 1000
four=iachar(s(4:4)) + 1000

a=(one-two)+(three-four)
b=(one-three)+(two-four)
c=(one-four)+(two-three)

if(a==0.or.b==0.or.c==0) then
write(*,'(a3)') 'Yes'
else
write(*,'(a2)') 'No'
end if
write(*,*) one, two, three, four
end program