def f(a, b, c):
    L = [a, b, c]
    if min(L) < 0:
        return 0
    L.sort()
    v = (L[-1] - L[0])//3
    L[-1] -= 2 * v
    L[0] += v
    return L

R, G, B = map(int, input().split())
L = [R, G, B]
L.sort()
R, G, B = L
ans = 0
for i in range(B//2 + 1):
    X = f(R + i, G, B - 2 * i)
    ans = max(ans, min(X))
print(ans)