import math

t, a, b = map(int, input().split())
lc = a // math.gcd(a, b) * b

# lcまでの出発回数
ldept = lc//a + lc//b - 1

ans = ldept * (t // lc)
t %= lc

# print(ldept, t, (t+a-1)//a, (t+b-1)//b)

ans += (t+a-1)//a
ans += (t+b-1)//b
if t != 0:
    ans -= 1

print(ans)