I need help from a physicsfag here

There was recently a question on my exam that asked the following question:
There is an ice cube in a glass of water. After the ice cube melts, how does the pressure at the bottom of the glass change?
I answered that it increases since the density of water is higher than that of ice, and the formula for hydrostatic pressure is p = h*rho*g, where p is hydrostatic pressure, rho is the density, and g is the gravitational constant, and g is the gravitational force of the Earth. However, the correct answer is that it doesn't change, since the mass of substance in the glass is unchanged. Can someone pls explain this to me?