A Class-A pan was setup adjacent to a lake for measuring evaporation losses in the lake. The depth of water in the pan at the beginning of a certain week was $250 \mathrm{~mm}$. In that week, there was a rainfall event with $10 \mathrm{~mm}$ depth. Water depth in the pan at the end of the week was $240 \mathrm{~mm}$. The pan coefficient is $0.8$.
The estimated lake evaporation during the week was _________ $\mathrm{mm}$ $\text{(an integer value)}$.
