What work must be done to get a stone weighing 5 kg and a volume of 2 dm3 from the bottom

What work must be done to get a stone weighing 5 kg and a volume of 2 dm3 from the bottom of the lake to the water surface? The depth of the lake is 7m.

Given:
m = 5kg,
g = 10m / s ^ 2,
ρ = 1000kg / m ^ 3,
V = 2dm ^ 3 = 0.002m ^ 3,
h = 7m;
Find a job A;
Mechanical work is equal to the product of the resultant force and the path:
A = F * h
The resultant force is equal to the difference between the force of gravity and the force of Archimedes acting on the stone:
F = m * g – ρ * g * V;
A = h * g * (m – ρ * V) = 7 * 10 * (5 – 1000 * 0.002) = 210J.