Throughout the fall, the squirrel worked hard to get enough food for the winter. Once, in search of mushrooms and nuts, the squirrel came across a lot of acorns.  She worked 3 nights, filling her hole in the hollow with acorns. On the first night, the squirrel collected half as many acorns as on the next two nights combined, and on the last night, one less acorn than on the previous two. How many acorns did the squirrel collect?