Kabovantsiv, or "karbovanets" is the Ukrainian word for "coupon" and was the unit of currency in
Ukraine until
hyperinflation forced Ukraine to replace it with the
Hryvnia.
Ukraine went through the worst inflation between 1993 and 1995. Before 1993, the highest denomination was 1,000 Karbovantsiv. By 1995, it was 1,000,000 Karbovantsiv.
Sources:
http://tomchao.com/hb18.html
http://www.uazone.net/Hryvnia/