program main
   implicit none 
   integer :: i,a,b,s 
   print*, "enter two numbers"
   read*, a,b 
   s = 0 
   do i=1, abs (b)
   if (b>0) then 
   s = s+a 
   else 
   s= s-a 
   end if 
   end do 
   print*, "answer",s
   
end program main