function spilitInput(input) {
  var splited = [];
  var rows = input.split('\n');
  for (var i = 0; i < rows.length; i += 1) {
    splited.push(rows[i].split(' '));
  }
  return splited;
}
function Main(input) {
  var splited = spilitInput(input);
  var N = splited[0][0];
  
  var counter = 0;
  for (var A = 1; A < N; A += 1) {
  for (var B = 1; (A * B) < N; B += 1) {
    counter += 1;
  }
  }

  console.log(counter);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));