from cmd import PROMPT


N,A,B = map(int,input().split())
if N%2==0:
    pppp = A*(N-1)-B*N 
    pmpm = -A*(N-1)
    print(min(pppp,pmpm))
else:
    pppp = A*(N-1)-B*N 
    pmpm = -A*(N-1)-B
    print(min(pppp,pmpm))