import sys
import functools

sys.setrecursionlimit(10000)

def memoize(obj):
    cache = obj.cache = {}

    @functools.wraps(obj)
    def memoizer(*args, **kwargs):
        if args not in cache:
            cache[args] = obj(*args, **kwargs)
        return cache[args]
    return memoizer

@memoize
def dfs(rest):
    if rest <= 0:
        return 0.0

    return min(dfs(rest - A) + 1, dfs(rest - D) + 1.5)


H, A, D = map(int, raw_input().split())
print dfs(H)