rgb = [int(x) for x in input().split()]
rgb.sort()

for i in range(2 * 10**7):
    if rgb[0] + 1 <= rgb[2] - 2 and rgb[0] < rgb[1] <= rgb[2]:
        rgb[0] += 1
        rgb[2] -= 2
    elif rgb[0] + 1 <= rgb[1] - 2 and rgb[0] < rgb[2] <= rgb[1]:
        rgb[0] += 1
        rgb[1] -= 2
    elif rgb[1] + 1 <= rgb[2] - 2:
        rgb[1] += 1
        rgb[2] -= 2
    elif rgb[2] + 1 <= rgb[1] - 2:
        rgb[2] += 1
        rgb[1] -= 2
    else:
        break
res = min(rgb)

print(res)