from math import gcd

def lcm(x, y):
    return (x*y)//gcd(x, y)

T, A, B = map(int, input().split())
ta = -(-T//A)
tb = -(-T//B)
tab = -(-T//lcm(A, B))
#print("ta",ta)
#print("tb",tb)
#print("tab",tab)
print(ta+tb-tab)