#include<cstdio>

 #include<queue>

 #define mp make_pair

 #define fi first

 #define sc second

 using namespace std;

 const int N = ;

 int n,m,a,b,i,j;

 int dp,p[N],pre[N],tt[N],o,vis[N],sum[N],id[N],ID[N];

 priority_queue<pair<int,int> > Q;

 void link(int x,int y)

 {

     dp++;pre[dp]=p[x];p[x]=dp;tt[dp]=y;

 }

 int main()

 {

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

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

     {

         scanf("%d%d",&a,&b);

         link(a,b);

         link(b,a);

     }

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

     Q.push(mp(,i));

     o=n;

     while (!Q.empty())

     {

         int x=Q.top().fi;

         int y=Q.top().sc;

         Q.pop();

         if (vis[y]) continue;

         if (x<sum[y]) continue;

         ID[y]=o;

         id[o--]=y;

         vis[y]=;

         i=p[y];

         while (i)

         {

             if (!vis[tt[i]])

             {

                 sum[tt[i]]++;

                 Q.push(mp(sum[tt[i]],tt[i]));

             }

             i=pre[i];

         }

     }

     for (i=;i<=n;i++) vis[i]=;

     for (j=;j<=n;j++)

     {

         int x=id[j],cnt1=,cnt2=,mi=0x37373737,y=;

         i=p[x];

         while (i)

         {

             if (ID[tt[i]]>j)

             {

                 if (ID[tt[i]]<mi) mi=ID[tt[i]],y=tt[i];

                 vis[tt[i]]=;cnt1++;

             }

             i=pre[i];

         }

         if (y)

         {

             i=p[y];

             while (i)

             {

                 if (vis[tt[i]]) cnt2++;

                 i=pre[i];

             }

         }

         if ((cnt1!=cnt2+)&&(y))

         {

             printf("Imperfect");

             return ;

         }

         i=p[x];

         while (i)

         {

             vis[tt[i]]=;

             i=pre[i];

         }

     }

     printf("Perfect");

 }