#include <fstream>

class InParser
{
#pragma warning (disable:4996)
private:
	FILE* fin;
	char* buff;
	int sp;
	char read()
	{
		++sp;
		if (sp == 4096)
		{
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}
public:
	InParser(const char* name)
	{
		fin = fopen(name, "r");
		buff = new char[4096];
		sp = 4095;
	}
	template <class T> 
	InParser& operator >> (T& n)
	{
		int sgn = 1;
		char c;
		while (!isdigit(c = read()));
		if (c == '-')
			sgn = -1;
		else n = c - '0';
		while (isdigit(c = read()))
			n = n * 10 + c - '0';
		n *= sgn;
		return *this;
	}
};

InParser fin("reguli.in");
std::ofstream fout("reguli.out");

const int NMAX = 5e5 + 1;

int pr[NMAX], n;
long long diff[NMAX], a, b;

void prefix()
{
	int k = 0;
	for (int i = 2; i < n; ++i)
	{
		while (k && diff[k + 1] != diff[i])
			k = pr[i];

		if (diff[k + 1] == diff[i])
			++k;

		pr[i] = k;
	}
}

int main()
{
	fin >> n >> a;

	for (int i = 1; i < n; ++i)
	{
		fin >> b;
		diff[i] = b - a;
		a = b;
	}

	prefix();

	--n;
	
	n -= pr[n];

	fout << n << '\n';
	for (int i = 1; i <= n; ++i)
		fout << diff[i] << "\n";

	fout.close();
	return 0;
}