#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <algorithm>
using namespace std;
// 深度优先搜索函数
bool dfs(const vector<int>& bricks, int currentIndex, int usedLayers, vector<int>& layerLengths, int maxLayers, int targetLength)
{
// 当所有积木都已使用完时，返回 true
if (currentIndex < 0)
{
return true;
}
// 当前层还未堆满，继续往上堆
if (usedLayers < maxLayers)
{
layerLengthsusedLayers = brickscurrentIndex;
if (dfs(bricks, currentIndex - 1, usedLayers + 1, layerLengths, maxLayers, targetLength))
{
return true;
}
layerLengthsusedLayers = 0;
}
// 把当前积木加入已有的每一层中，看是否能够满足条件
for (int i = 0; i < usedLayers; i++)
{
// 如果当前层和上一层积木长度相同，则不需要重复计算
if (i > 0 && layerLengthsi == layerLengthsi - 1)
{
continue;
}
// 如果当前积木可以放入当前层，则把当前积木放入当前层
if (layerLengthsi + brickscurrentIndex <= targetLength)
{
layerLengthsi += brickscurrentIndex;
if (dfs(bricks, currentIndex - 1, usedLayers, layerLengths, maxLayers, targetLength))
{
return true;
}
layerLengthsi -= brickscurrentIndex;
}
}
return false;
}
int main()
{
// 读取输入
string inputStr;
getline(cin, inputStr);
istringstream iss(inputStr);
vector<int> bricks;
int brick;
while (iss >> brick)
{
bricks.push_back(brick);
}
// 计算所有积木的总长度
int totalLength = 0;
for (int brick : bricks)
{
totalLength += brick;
}
// 对积木长度进行排序
sort(bricks.begin(), bricks.end());
int maxLayers = -1;
// 遍历所有可能的层数
for (int i = 2; i <= totalLength; i++)
{
// 如果所有数字的和除不尽层数，自然肯定不满足条件
if (totalLength % i != 0)
{
continue;
}
// 计算每一层的目标长度
int targetLength = totalLength / i;
// 如果最大的积木长度大于当前层的长度，则无法满足条件
if (bricks.back() > targetLength)
{
continue;
}
// 初始化每层的长度列表
vector<int> layerLengths(i, 0);
// 使用深度优先搜索判断是否可以堆成满足条件的墙
if (dfs(bricks, bricks.size() - 1, 0, layerLengths, i, targetLength))
{
maxLayers = max(maxLayers, i);
}
}
// 输出最大层数
cout << maxLayers << endl;
return 0;
}