  We propose an ansatz for the nonperturbative beta function of a generic
non-supersymmetric Yang-Mills theory with or without fermions in an arbitrary
representation of the gauge group. While our construction is similar to the
recently proposed Ryttov-Sannino all order beta function, the essential
difference is that it allows for the existence of an unstable ultraviolet fixed
point in addition to the predicted Bank-Zaks -like infrared stable fixed point.
Our beta function preserves all of the tested features with respect to the
non-supersymmetric Yang-Mills theories. We predict the conformal window
identifying the lower end of it as a merger of the infrared and ultraviolet
fixed points.
