import strutils, sequtils, algorithm

var
  RGB = map(split readLine stdin, parseInt)
  ans = 0
let
  m = min RGB

ans += m
for i, v in RGB:
  RGB[i] -= m

while true:
  sort(RGB, cmp, Descending)
  let n = min(RGB[1], RGB[0] div 3)
  if n <= 0:
    break
  ans += n

  if n == RGB[1]:
    RGB[0] -= 3 * n
    RGB[1] = 0

  else:
    RGB[1] -= n
    RGB[0] = RGB[0] mod 3

echo ans