R,G,B = map(int,input().split())

left = -1
right = 10**9 + 1

ans = 0

def search(mid,R,G,B):
    count = 0
    count += min(R,G,B)
    R -= count
    G -= count
    B -= count
    s = 0
    if(R != 0 and R % 2 == 0):
        s += 1
    if(G != 0 and G % 2 == 0):
        s += 1 
    if(B != 0 and B % 2 == 0):
        s += 1   
    t = R + G + B
    if(s != 2 and s != 0):
        count += t // 4
    else:
        if((t //4 ) % 2 != s % 2):
            count += (t // 4) 
            count -= 1
        else:
            count += t // 4
    return count        



while abs(left - right) > 1:
    mid = (left + right) // 2
    if(search(mid,R,G,B) >= mid):
        left = mid
        ans = max(ans,mid)
    else:
        right = mid   
print(ans)