program Takoyaki
    implicit none
    integer n, x, t  !最大個数、個数、時間
    integer s, a, b, c

    read *, n, x, t

    a=n/x
    b=mod(n,x)
    c=0
    if(b/=0) then
        c=1
    end if
    s=t*(a+c)
    print *, s 
end program Takoyaki