At the instant of vertical launch the rocket expels exhaust at the rate of $220 \mathrm{kg} / \mathrm{s}$ with an exhaust velocity of $820 \mathrm{m} / \mathrm{s}$. If the initial vertical acceleration is $6.80 \mathrm{m} / \mathrm{s}^{2},$ calculate the total mass of the rocket and fuel at launch.