import sys
import math
input = lambda: sys.stdin.readline().rstrip()


def solve():
    n, a, b = map(int, input().split())  
    lcm = (a*b)//math.gcd(a, b)
    ans = n - (n//a + n//b) + n//lcm
    print(ans)

t = 1
# t = int(input())
for _ in range(t):
    solve()