T,A,B = list(map(int, input().split()))
def gcd(a, b):
    if b == 0:
        return a
    else:
        return gcd(b, a%b)
def lcm(a, b):
    return a * b // gcd(a,b)

print((T+A-1) // A + (T+B-1) // B - (T+lcm(A,B)-1) // lcm(A,B))