The standard enthalpies of formation of $C_6H_6(l)$, $CO_2(g)$ and $H_2O(l)$ are respectively $+49\text{kJ mol}^{-1}$, $-394\text{kJ mol}^{-1}$ and $-286\text{kJ mol}^{-1}$ respectively. What is the value of standard enthalpy of combustion of $C_6H_6(l)$?