import math

def calc(a,b):
    if a%b == 0:return a//b
    else:return (a//b)+1
T,A,B = map(int,input().split())
C = int(A*B/math.gcd(A,B))

times_a = calc(T,A)
times_b = calc(T,B)
times_c = calc(T,C)
print(times_a+times_b-times_c)