#!/usr/bin/env python3
h, a, d = map(int, input().split())
def e(i, memo={}):
    if i <= 0:
        return 0
    else:
        if i not in memo:
            memo[i] = min(1 + e(i-a), 3/2 + e(i-d))
        return memo[i]
print(e(h))