If both roots of the quadratic equation x² + 2(λ + 1)x + λ² + λ + 7 = 0 are distinct and less than the minimum value of the function $\mathrm{f}\left(\mathrm{\theta }\right)=1+\frac{\mathrm{cos\theta }-\mathrm{sin\theta }-\cos 3\mathrm{\theta }+\sin 3\mathrm{\theta }}{2(\sin 2\mathrm{\theta }+2{\cos }^2\mathrm{\theta }-1)}$ (where $\mathrm{\theta }\in \mathrm{R}$), then  the least integral value of λ is