def gcd(a, b): return gcd(b, a % b) if b > 0 else a;

def add_v(a, b):
    ret = a // b
    if a % b != 0: ret += 1;
    return ret

T, A, B = map(int, input().split(' '))
ans = add_v(T, A) + add_v(T, B)
G = gcd(A, B)
L = A * B // G
ans -= add_v(T, L)
print(ans)