RGB = list(map(int, input().split()))
RGB.sort()
R, G, B = RGB
lb = 0
ub = max(RGB) + 1


def check(x):
    if R >= x:
        return True
    if B < x:
        return False
    short = x - R
    if G < x:
        if (B - x) // 2 < short + x - G:
            return False
        else:
            return True
    else:
        if short > (G - x) // 2 + (B - x) // 2:
            return False
        else:
            return True


while ub - lb > 1:
    mid = (ub + lb) // 2
    if check(mid):
        lb = mid
    else:
        ub = mid

print(lb)