Initially a bottle contained $400 \mathrm{~g}$ of ethanol. Half of ethanol was used by a student for preparing the stock solution in an environmental chemistry laboratory just before summer vacation of $90$ days. After completing the procedure, the student left the bottle uncorked. If the unsealed bottle losses ethanol at a rate of $0.5 \mathrm{~g} /$ day, the ethanol that will be left in the bottle at the end of the summer vacation is ___________ $\mathrm{g}$ $\text{(an integer value)}$.
