Calculate the standard enthalpy of formation for diamond, given?

Calculate the standard enthalpy of formation for diamond, given that
C(graphite) + O2(g) → CO2(g) ΔH0 = –393.5 kJ/mol
C(diamond) + O2(g) → CO2(g) ΔH0 = –395.4 kJ/mol

Is it 1.9 or -1.9 and why?
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