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())
c = lcm(a,b)
sum = 0
sum += t//a+(1 if t%a!=0 else 0)
sum += t//b+(1 if t%b!=0 else 0)
sum -= t//c+(1 if t%c!=0 else 0)

print(sum)