//This program gets data from file "input.txt" and return queue of correct order
//of the courses or NIE if it's impossible to reach all course

//If it's possible, it return queue and code 0. If it's not possible,
//return NIE and code 5.


#include <iostream>
#include <fstream>
#include <queue>

using namespace std;

//Checking the course
//It's checking new requirement to see if after adding,
//we can reach all course. If it's not possible, end this program.

void requirement(bool Tab[],int n, int Where, int KeyWord){
    for(int i=Where*n;i<Where*n+n;i++){
        if(Tab[i]){
            if (i%n==KeyWord){
                cout<<"NIE";
                exit(3);
            }
            requirement(Tab,n,i%n,KeyWord);
        }
    }
}

//Push to queue result
//It looks deeper into the connections and adds them to the
//queue from the deepest course.
void makeQueue(queue<int> *Res,bool Tab[],int n,int CurrentElement){

    for(int i=CurrentElement*n;i<CurrentElement*n+n;i++)
        if(Tab[i])
            makeQueue(Res,Tab,n,i%n);

    for(int i=0;i<n*n;i+=n)
        Tab[CurrentElement+i]=false;

    Res->push(CurrentElement);
}

int main() {
    fstream OFile;
    OFile.open("input.txt", ios::in);
    if(OFile.good()){
        //Getting n and m
        int n, m;
        OFile>>n;
        OFile>>m;
		//Making table for all connections between courses.
        bool Table [n*n];
        for(int i=0;i<n*n;i++)
            Table[i]=false;


		//Getting all connections
        for(int i=0,temp_1,temp_2;OFile.good();i++){
            OFile>>temp_1;
            OFile>>temp_2;
            if(temp_1>n-1 || temp_2>n-1 || i>m*2){
                cout<<"\n\nCorrupted file!\n\n";
                return 2;
            }
            if(temp_1==temp_2){
                cout<<"NIE";
                return 3;
            }else{
                requirement(Table,n,temp_2,temp_1);
                Table[temp_1*n+temp_2]=true;
            }
        }
        OFile.close();

        queue<int> Result;

		//Adding all courses in order.
        for (int i=0;Result.size()!=n;i++){
            makeQueue(&Result,Table,n,i);
        }
        cout<<"-----------\n";
        for(int i=0;i<n;i++){
            cout<<Result.front()<<" ";
            Result.pop();
        }
    }else{
        cout<<"\n\ninput.txt error!\n\n";
        return 1;
    }
    return 0;
}

/*Output

	0 - all correct,
	1 - missing files,
	2 - file "input.txt" have incorrect data,
	3 - it's impossible to reach all courses,
	4 - Do adding not addicting :p (ExplosmEntertainment).


*/