program sample
    implicit none
    character(100)::s,t
    integer(8) :: i,j,k,m,n
    integer(8)::a,b,c,d
    integer(8),allocatable::x(:),y(:)
  
    read(*,*)n,a,b 
    if(mod(n,a)==0)then
        write(*,*)n/a*b
    else
        write(*,*)(n/a+1)*b
    end if
    
    stop
end program sample
  

