The circle easier solution

      R = sqrt(4.0)

      num = 0.0

      do 10 i=-R,R
         do 20 j=-R,R

            instR = ((i**2) + (j**2) )**(0.5)
            if(instR.LT.R) num = num + 1

 20      continue
 10   continue

      write (*,*)num

      pause
      stop
      end