import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")
from math import gcd

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	T, A, B = getlist()
	GCD = gcd(A, B)
	LCM = int(A * B // GCD)
	ans = int((T - 1) // A + 1) + int((T - 1) // B + 1) - (int(T - 1) // LCM + 1)
	print(ans)

if __name__ == '__main__':
	main()