Pharaoh's cows and ears of grain

In the story, Pharaoh dreams that he is standing by the river. Seven healthy, well-fed cows come up out of the water, followed by seven thin, starved cows, and the thin cows eat the fat ones. He wakes, sleeps again and dreams of seven full ears of grain on one stalk, swallowed by seven thin ears scorched by the east wind.

None of Pharaoh's advisers can explain the dreams. His chief butler remembers a young Hebrew prisoner, Joseph, who once explained the butler's own dream correctly. Joseph is brought from prison and says the two dreams are one: seven years of plenty are coming, followed by seven years of famine.