n, a, b = map(int, input().split())

sgn = [1, -1]

dp = [- b * sgn[i] for i in range(2)]
for _ in range(n - 1):
  ndp = [INF for _ in range(2)]
  ndp[0] = min(dp[0] + a - b, dp[1] - a - b)
  ndp[1] = min(dp[0] - a + b, dp[1] + a + b)
  dp = ndp

print(min(dp))