*Problem #4*

A game of solitaire is played as follows. After each play, according to
the outcome, the player receives either *a* or *b* points
(*a* and *b* are positive integers with *a* greater
than *b*), and his score accumulates from play to play. It has
been noticed that there are thirty-five non-attainable scores and
that one of them is 58. Find *a* and *b*.
Source: Putnam Competition, 1971