#include <iostream>

 #include<cstdio>

 #include<cstring>

 #include<stdlib.h>

 #include<algorithm>

 #include<vector>

 using namespace std;

 vector<int>ed[];

 int x,y,flag,g,f[],o[],n,q[];

 int co[],a[],b[],dp[][];

 int vis[],p[][][];

 void dfs(int u,int c)

 {

     int i;

     if(co[u]==)

     {

         x++;

         p[g][x][] = u;

     }

     else

     {

         y++;

         p[g][y][] = u;

     }

     for(i =  ; i < (int)ed[u].size() ; i++)

     {

         int v = ed[u][i];

         if(co[v])

         {

             if(co[v]!=-c)

             {

                 flag = ;

                 return ;

             }

         }

         else

         {

             co[v] = -c;

             dfs(v,-c);

         }

     }

 }

 void dfs2(int s,int v)

 {

     if(flag) return ;

     int i;

     if(s==)

     {

         if(v==)

         {

             flag = ;

             return ;

         }

         else

         return ;

     }

     for(i = ; i <= g ;i++)

     {

         if(!vis[i]&&s-a[i]>=&&dp[v-][s-a[i]])

         {

             f[i] = ;

             vis[i] = ;

             dfs2(s-a[i],v-);

             if(flag) return;

             f[i] = ;

             vis[i] = ;

         }

         if(!vis[i]&&s-b[i]>=&&dp[v-][s-b[i]])

         {

             f[i] = ;

             vis[i] = ;

             dfs2(s-b[i],v-);

             if(flag) return ;

             vis[i] = ;

             f[i] = ;

         }

     }

 }

 int main()

 {

     int m,i,j;

     scanf("%d%d",&n,&m);

     for(i = ; i <= m ; i++)

     {

         int u,v;

         scanf("%d%d",&u,&v);

         ed[u].push_back(v);

         ed[v].push_back(u);

     }

     for(i = ; i <= *n ; i++)

     {

         if(!co[i])

         {

             g++;x=;y=;

             co[i] = ;

             dfs(i,);

             a[g] = x;

             b[g] = y;

         }

         if(flag)

         break;

     }

     if(flag)

     {

         puts("IMPOSSIBLE\n");

         return ;

     }

     else

     {

         dp[][] = ;

         for(i = ; i <= g ; i++)

         for(int k = g; k >=  ; k--)

         {

             for(j = n ; j >=  ; j--)

             {

                 if(j>=a[i])

                 dp[k][j] = max(dp[k][j],dp[k-][j-a[i]]);

                 if(j>=b[i])

                 dp[k][j] = max(dp[k][j],dp[k-][j-b[i]]);

             }

         }

         if(!dp[g][n])

         puts("IMPOSSIBLE");

         else

         {

             dfs2(n,g);

             for(i = ; i <= g ; i++)

             if(f[i])

             {

                 if(f[i]==)

                 for(j =  ; j <= a[i] ; j++)

                 {

                     printf("%d ",p[i][j][]);

                     q[p[i][j][]] = ;

                 }

                 else

                 for(j =  ; j <= b[i] ; j++)

                 {

                     printf("%d ",p[i][j][]);

                     q[p[i][j][]] = ;

                 }

             }

             puts("");

             for(i = ; i <= *n ;i++)

             if(!q[i])

             printf("%d ",i);

             puts("");

         }

     }

     return ;

 }