The reaction of cyanamide, NH₂CN_(s) with oxygen was run in a bomb calorimeter and $\Delta$U was found to be $-$742.24 kJ mol^$-$1. The magnitude of $\Delta$H₂₉₈ for the reaction

$N{H_2}C{H_{(S)}} + {3 \over 2}{O_{2(g)}} \to {N_{2(g)}} + {O_{2(g)}} + {H_2}{O_{(I)}}$

is _________ kJ. (Rounded off to the nearest integer) [Assume ideal gases and R = 8.314 J mol^$-$1 K^$-$1]