# wiek = 15
# rok = 2026

# for i in range (wiek + 1):
#     realRok = (rok - wiek) + i
#     if realRok == rok:
#          print(f"w tym roku masz {i} lat")
#     else:
#         print(f"w roku {realRok} miales {i} lat")

# for i in range (1, 11):
#     line =""
#     for e in range (1, 11):
#         line += str(i*e).center(6)
#     print(line)

# liczbaLin = int(input("podaj liczbe linijek"))

# lin = 0

# for i in range (1, liczbaLin +1):

# for i in range (1, liczbaLin):
#     breakk = ""
#     for i in range (1, liczbaLin - lin):
#          breakk += " "
#     lin += 1
#     line = ""
   
#     for i in range (1, lin):
#         line += " *"
#     print(str(breakk + line))
    
# h = int(input("podaj wysokosc"))
# w = int(input("podaj szerokosc"))
# line = ""

# for i in range (1, h +1):
#     if i == 1:
#         line = ""
#         for i in range (1,w):
#             line += "*"
#     elif i == h:
#          line = ""
#          for i in range (1,w):
#             line += "*"
#     else:
#         line = ""
#         breakk = ""
#         for i in range (1,w-2):
#             breakk += " "
#         line += "*" + breakk + "*"
#     print(line)

# for i in range (1,21):
#     if (i%3) == 0 and (i%5) == 0:
#         print("FizzBuzz")
#     elif (i % 3) == 0:
#         print("Fizz")
#     elif (i % 5) == 0:
#         print("Buzz")
#     else:
#         print(i)

cd = int(input("podaj liczbe calkowita dodatnia"))
count = 0
for i in range(1,cd+1):
    if i%2 == 0 or i%3 == 0:
        count += i
print(count)