rgb = list(map(int, input().split()))
rgb.sort()
ans = 0
while 1:
    x = rgb[0]
    ans += x
    rgb[0] -= x
    rgb[1] -= x
    rgb[2] -= x
    if rgb[2] <= 2:
        break
    rgb[0] += 1
    rgb[2] -= 2
    rgb.sort()
print(ans)