var inputs = Console.ReadLine().Split(' ');
var n = long.Parse(inputs[0]);
var a = long.Parse(inputs[1]);
var b = long.Parse(inputs[2]);
long GCD(long x, long y) => y == 0 ? x : GCD(y, x % y);
var ans = n - (n / a) - (n / b) + (n / (a * b / GCD(a, b)));
Console.WriteLine(ans);