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