import math
N,a,b=map(int, input().split())

min_ab=a*b//math.gcd(a,b)
a_times=N//a
b_times=N//b
ab_times=(N//min_ab) 
ans=a_times+b_times-ab_times+1

if N%min_ab==0:
    print(ans-1)
else:
    print(ans)