l = map(int, raw_input().split())

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

t=l[0]
a=l[1]
b=l[2]

if t%a==0:
    ans=t/a;
else:
    ans=t/a+1;

if t%b==0:
    ans+=t/b;
else:
    ans+=t/b+1;

tmp=(a * b) // gcd(a, b)

if t%tmp==0:
    ans-=t/tmp;
else:
    ans-=t/tmp+1;

print(ans);