let n = Int(readLine()!)!
var dpTable = [Int](repeating: 0, count: 1000000+1) // dpTable
var cutter = [Int](repeating: 0, count: 1000000+1) // divisor count
dpTable[2] = 1 

for it in 1...1000000 {
  var k = 1
  while k * it <= 1000000 {
    cutter[k*it] += 1
    k += 1
  }
}

if n > 2 {
  for it in 3...n {
   dpTable[it] = dpTable[it-1] + cutter[it-1]
  }
}

print(dpTable[n])