import sequtils,algorithm,math
proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int =
  while true:
    var k = getchar_unlocked()
    if k < '0': break
    result = 10 * result + k.ord - '0'.ord

template times*(n:int,body) = (for _ in 0..<n: body)
template `max=`*(x,y) = x = max(x,y)
template `min=`*(x,y) = x = min(x,y)

var rgb = @[scan(),scan(),scan()]
rgb = rgb.filterIt(it > 0)
var ans = 0
while true:
  rgb = rgb.filterIt(it > 0)
  # echo rgb,ans
  if rgb.len == 3: # 5 18 36
    var del = rgb.min()
    rgb = rgb.mapIt(it - del)
    ans += del
  elif rgb.len == 2: # 0 13 31
    let x = rgb.max()
    let y = rgb.min()
    var n = (x - y) div 2
    if n > 1 and n >= x - n * 2: n = n div 2
    if n == 0 :
      if x == 2: break
      rgb = @[x mod 4,y mod 4]
      ans += y div 4 * 2
    else:
      rgb = @[x - n * 2, y , n ] # 9 13 13
  elif rgb.len == 1:
    let r = rgb[0]
    if r <= 4: break
    rgb = @[1,1,r - 4]
  else: break
echo ans