#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
import bisect
import heapq


def input():
    return sys.stdin.readline()[:-1]


# sys.setrecursionlimit(1000000)

# _INPUT = """# paste here...
# """
# sys.stdin = io.StringIO(_INPUT)

T, A, B = map(int, input().split())
T -= 1
ans = (T//A+1) + (T//B+1) - (T//(A*B//math.gcd(A,B))+1)
print(ans)