top_BFS();

// In the name of Allah.
// We're nothing and you're everything.
// Ya Ali!
/*
                  ,     \    /      ,
                 / \    )\__/(     / \
                /   \  (_\  /_)   /   \
           ____/_____\__\@  @/___/_____\____
          |             |\../|              |
          |              \VV/               |
          |        ------___-------         |
          |__________Chuta Dragon___________|
           |    /\ /      \\       \ /\    |
           |  /   V        ))       V   \  |
           |/     `       //        '     \|
           `              V                '
*/

#include<bits/stdc++.h>
using namespace std;
typedef long long  ll;
typedef pair<ll,ll> pll;
#define fastread() (ios_base:: sync_with_stdio(false),cin.tie(NULL))
#define fi first
#define se second
#define pb push_back
ll const MOD=1000000007;
const int M= 2e5 + 10;
///-------------------------------------------------------------------------------------------------///
///                KARMA IS LIKE 69,,, YOU GET WHAT YOU GIVE                                        ///
///-------------------------------------------------------------------------------------------------///
#define eb emplace_back

vector<ll>v[M+10];
ll n,m;
bool vis[M+10];
ll cost[M+1];
queue<ll>q;
vector<ll>ans;
void top_BFS()
{




    while(!q.empty())
    {
        ll u=q.front();
        q.pop();
        //cout<<u<<endl;
   ans.push_back(u);
       for(auto x:v[u])
       {
           cost[x]--;
           if(!cost[x])
           {

            q.push(x);

           }


       }

    }


}


void input()
{

     cin>>n>>m;

    ll a,b;
    for(ll i=0;i<m;i++)
    {
        cin>>a>>b;

       v[a].eb(b);

       cost[b]++;

    }
}


int main()
{
    fastread();

    input();


    for(ll i=1;i<=n;i++)
    {
        if(!cost[i])q.push(i);

    }



    top_BFS();



     if(ans.size()==n)
     {
        for(auto x:ans)cout<<x<<endl;


    }else cout<<"IMPOSSIBLE"<<endl;




}
/*

6 6
1 2
1 3
2 4
2 6
3 5
3 4