Photons of red light have a wavelength of approximately $7\times 10^{-7}$ meters. The energy of a photon is inversely proportional to its wavelength. A photon with 2000 times the energy as a photon of red light will have a wavelength that can be written as $a\cdot 10^b$ meters, where $1\le a < 10$. (In other words, in scientific notation.) What is $a+b$ written as a decimal?