Refrigerant vapor enters into the compressor of a standard vapor compression cycle at −$10^\circ C \:(h = 402 \: kJ/kg)$ and leaves the compressor at $50^\circ C \: (h = 432 \: kJ/kg)$. It leaves the condenser at $30^\circ C \: (h = 237 \: kJ/kg)$. The COP of the cycle is ________