DIM A, B, T, M, R AS INTEGER
A = -19: B = 19
M = A: R = F(A)
FOR T = A TO B
  IF F(T) <= R THEN
    M = T
    R = F(T)
  END IF
NEXT T
PRINT R-M

FUNCTION F(x)
  F = (x*x-90)*(x*x-90) + 6
END FUNCTION