4. A, B, and C went to the orchard to pick oranges, and they picked a total of 108 oranges. A first gave half of his oranges to B, then B gave $\frac{1}{5}$ of his oranges at that time to C, and finally C gave $\frac{1}{7}$ of his oranges at that time to A. If at this point the three of them had the same number of oranges, how many oranges did each of them initially pick?