N, A, B = map(int, input().split())

# -1 1 -1 1 ...
up = N // 2
down = N - up
answer1 = -A * (N - 1) - B * (down - up)
# 1 1 1 1 ...
answer2 = A * (N - 1) - B * N

print(min(answer1, answer2))