r, g, b = map(int, input().split())

if r > g:
    r, g = g, r
if g > b:
    g, b = b, g
if r > g:
    r, g = g, r

while b - r > 2:
    b -= 2
    r += 1

    if r > g:
        r, g = g, r
    if g > b:
        g, b = b, g
    if r > g:
        r, g = g, r

print(r)