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

def lcm(a,b):
    if a*b == 0:
        return 0
    else:
        return a // gcd(a,b) * b
        

t,a,b = map(int,input().split())
print(t//a+t//b-t//lcm(a,b))