#include <queue>
#include <iostream>
#include <vector>
#include <cstring>
#include <iostream>
#include <set>
#include <cstring>
#include <stack>
//#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 3e5 + 10;
const ll INF = 3e16 + 10;
vector<int> graph[maxn];
bool visited[maxn];
int color_node[maxn];

stack<int> st;
bool is_cycle(int node) {
    color_node[node] = 1;
    for(int i = 0; i < (int) graph[node].size(); i++) {
        int neighbour = graph[node][i];
        if(color_node[neighbour] == 1) {
            return true;
        }
        if(color_node[neighbour] == 0) {
            if(is_cycle(neighbour)) {
                return true;
            }
        }
    }
    color_node[node] = 2;
    return false;
}
void dfs(int node) {
    visited[node] = true;

    for(int i = 0; i < (int) graph[node].size(); i++) {
        int neighbour = graph[node][i];
        if(!visited[neighbour]) {
            dfs(neighbour);
        }
    }
    st.push(node);
}
int main() {
    ios_base::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;

        for(int j = 0; j < m; j++) {
            int a, b;
            cin >> a >> b;
            a--; b--;
            graph[a].push_back(b);

    }
    for(int i = 0; i < n; i++) {
        color_node[i] = 0;
    }
    for(int i = 0; i < n; i++) {
        if(color_node[i] == 0) {
            if(is_cycle(i)) {
                cout << "IMPOSSIBLE" << endl;
                return 0;
            }
        }
    }

    for(int i = 0; i < n; i++) {
        if(!visited[i]) {
            dfs(i);
        }
    }
    while(!st.empty()) {
        cout << st.top() + 1 << " ";
        st.pop();
    }
    return 0;
}