program name
    use,intrinsic :: iso_fortran_env
    implicit none
    integer(int64):: k,a,b,ans

    read*, k,a,b
    ans=a + ((k-(a-1))/2)*(b-a)
    if (mod(k-(a-1),2_8) == 1) ans=ans+1
    print'(i0)', max(k+1,ans)
end program name