What looks like a backward R is the Cyrillic letter "ya," which is the final letter of the Cyrillic
alphabet. Alone, the letter is the first person singular pronoun in Russian and some other Slavic languages.
Your coins are both Russian fractional dengas or kopecks, hammered silver "wire
money" (so called because of their mode of manufacture).
These were made under several late
Medieval Czars and depict either St. George or,as some authorities suggest, the Czar on horseback with a spear. St. George seems more likely, although no dragon is portrayed.
These are, as Snegovik states, coins of Michael Fyodorovich Romanov (
his name is partly readable on the second and third lines of both coins -- in the old
style of the Cyrillic
alphabet then in use) and would have been struck sometime between 1613 and 1645.
