John had some marbles. He gave half of them to Mabel.

Mabel had some beads. She gave half of them to John.

John then gave 10 beads away and Mabel gave 112 marbles away.

As a result, the ratio of John’s marbles to beads became 4:1 and the ratio of Mabel’s marbles to beads became 2: 1.

How many marbles did John have at first?