from math import gcd

def lcm(a, b):
    return a * b // gcd(a, b)

T, A, B = map(int, input().split())
ans1 = T // A + 1 + (-1 if T % A == 0 else 0)
ans2 = T // B + 1 + (-1 if T % B == 0 else 0)
L = lcm(A, B)
ans3 = T // L + 1 + (-1 if T % L == 0 else 0)

print(ans1 + ans2 - ans3)