def judge(x):
    plus = []
    minus = []
    cnt = 0
    
    for i in [R, G, B]:
        if i > x:
            plus.append(i - x)
        else:
            minus.append(x - i)
    
    for plus_i in plus:
        cnt += plus_i // 2
    
    if cnt >= sum(minus):
        return True
    else:
        return False
        
def binary_search():
    left, right = 0, (R+G+B) // 3
    
    while left <= right:
        mid = (left + right) // 2
        
        if judge(mid):
            left = mid + 1
        else:
            right = mid - 1
    
    return right

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