import  numpy as np
t,a,b=map(int,input().split())
tmp=np.lcm(a,b)
if t>=tmp:
    cnt=0
    cnt+=tmp//a
    cnt+=tmp//b
    cnt-=1

    b=t//tmp
    cv=t%tmp
    ans=cnt*b
    for i in range(0,cv+1):
        if i%a==0 or i%b==0:
            ans+=1

    print(ans-1)

else:
    ans=t//a+t//b
    print(ans)