#include <iostream>
#include <vector>

using namespace std;

int INTMAX = 0x7FFFFFFF;

vector<int> solution;
vector<int> maxVals;
vector<int> maxPaths;
vector<int> v;
vector<vector<int>> r;

static void GetSolutionPath(int index)
{
	solution.push_back(index + 1);
	if (maxPaths[index] != -1)
	{
		GetSolutionPath(maxPaths[index]);
	}
}

static int GoBack(int index)
{
	if (maxVals[index] != -1)
	{
		return maxVals[index];
	}
	vector<int> backPaths = r[index];
	int maxVal = -INTMAX;
	int save = 0;

	int length = backPaths.size();
	for (int i = 0; i < length; i++)
	{
		int val = GoBack(backPaths[i]);
		if (val > maxVal)
		{
			maxVal = val;
			save = backPaths[i];
		}
	}
	maxVals[index] = maxVal + v[index];
	maxPaths[index] = save;
	return maxVal + v[index];
}

int main()
{
	int n, m;
	cin >> n >> m;

	for (int i = 0; i < n; i++)
	{
		int x;
		cin >> x;
		v.push_back(x);
		maxPaths.push_back(-1);
		maxVals.push_back(-1);
		r.push_back(vector<int>());
	}
	maxVals[0] = v[0];
	for (int i = 0; i < m; i++)
	{
		int from, to;
		cin >> from >> to;
		r[to - 1].push_back(from - 1);
	}
	int returnVal = GoBack(n - 1);
	if (returnVal >= 0)
	{
		cout << returnVal << endl;
		GetSolutionPath(n - 1);

		int l = solution.size();
		for (int i = l - 1; i >= 0; i--)
		{
			cout << solution[i] << " ";
		}
	}
	else
	{
		cout << -1;
	}
}