h, a, d = map(int, input().split())
dp = [0] * (h + 1)
for i in range(1, h + 1):
    dp[i] = min(2 + dp[max(0, i - a)], 3 + dp[max(0, i - d)])
print(dp[h] / 2 if dp[i] % 2 else dp[h] // 2)