28237
 13190
 39914
 81367
 8554
 61106
 67448
 39004
 22308
 16054
 71468
 60501
 100
 300
 59632
 90783
 5611
 1000
 69475
 69753
 10
 5
 582
 8
 36961
 5071
 20
 53213
 92775
 28738
 100000
 92280
 37944
 9
 2627
 7
 3

1028306548 224346172 2054738392 8539207488 94344524 4816051228 5867563092 1962150044 641839188 332342852 6587875268 4721174212 12600 115440 4586497300 10630118936 40580456 1286328 6225539588 6275533596 92 8 434692 52 1762017168 33141852 440 3652070664 11101694484 1065137992 12898363344 10983871880 1856988304 64 8885348 28 0
import math

n = int(input())

notPrime = [0] * 100001
toConsider = [0] * 100001
divisible = [0] * 100001

notPrime[0] = 1;
notPrime[1] = 1;

for i in range(2, n + 1):
  for j in range(i * 2, n + 1, i):
    notPrime[j] = 1

toConsider[2] = 1

for i in range(3, n + 1):
  if(i * 2 > n):
    break

  if(notPrime[i] == 0):
    toConsider[i] = 1

for i in range(2, n + 1):
  if(toConsider[i] == 1):
    for j in range(i, n + 1, i):
      divisible[j] = 1

sum = 0

for i in range(4, n + 1):
  sq = int(math.sqrt(i))
  
  sq += 2
  for j in range(2, sq, 1):
    if i % j == 0:
      if(divisible[j]):
        sum += i // j

sum *= 4

print(sum)