Hãy so sánh S với 1/2

Cho S = $\frac{1}{11}+\frac{1}{12}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{16}+\frac{1}{17}+\frac{1}{18}+\frac{1}{19}+\frac{1}{20}$.
Hãy so sánh S với $\frac{1}{2}$.