Original title: Р.К.Шранка, К.М.Подниекс. Надежность релейно-контактных схем при достаточно надежных контактах. Автоматика и вычислительная техника, 1973, 4, 44-48. [[[[[]]]]] It is shown that, for sufficiently reliable contacts, the reliability of S - P circuits that implement an n-position symmetrical quasi-monotonic function with indexes k and l is defined by the minimum probability of correct operation for not more than four input states. In certain cases (when there are certain relationships between k, l, and n) the number of input states which must be examined drops to two.