def gcd(i,j):
    if j ==0:
        return i
    else:
        return gcd(j,i%j)

def lcm(i,j):
    return (i//gcd(i,j)) * j

def main():
    t,a,b = map(int,input().split())
    p = lcm(a,b)
    print((t+a-1)//a + (t+b-1)//b - (t+p-1)//p)

if __name__ == '__main__':
    main()