Find the heat Q₄₋₂₋₁, which is added to the gas in the process 4-2-1

In the process of taking a gas from state 1 to state 4 along the curved path the heat leaves the system is Q₁₋₄ and the work done on the system is W₁₋₄.

When the gas is taken along the path 4-2-1, the work done by the gas is W₄₋₂₋₁. Find the heat Q₄₋₂₋₁, which is added to the gas in the process 4-2-1, in terms of Q₁₋₄, W₁₋₄, W₄₋₂₋₁