A fly with a mass of $1.0 \times 10^{-4} \mathrm{~kg}$ crawls across a table at a speed of $2 \mathrm{~mm} / \mathrm{s}$. Compute the de Broglie wavelength of the fly and compare it to the size of a proton (about $1 \mathrm{fm}, 1 \mathrm{fm}=10^{-15} \mathrm{~m}$ ).