Codeforces Round #657 (Div. 2) B. Dubious Cyrpto(暴力/数学)
Pashalovestosendstrictlypositiveintegerstohisfriends.Pashacaresaboutsecurity,thereforewhenhewantstosendanintegernn,heencryptsitinthefollowingway:hepicksthreeintegersaa,bbandccsuchthatl≤a,b,c≤rl≤a,b,c≤