#include <cstdio>#include <cstring>using namespace std;int n, m;bool g[1024][1024], used[1024];int lable[1024], set[1024]; void Relable() { memset(used, false, sizeof(used)); used[1] = true; for (int num=n-1; num>0; num--) { memset(lable, 0, sizeof(lable)); for (int i=1; i<=n; i++) { if (!used[i]) { for (int j=1; j<=n-num; j++) { if (g[i][set[n-j+1]]) lable[i]++; } } } int maxv = 0, max; for (int i=1; i<=n; i++) { if (lable[i] > maxv) { maxv = lable[i]; max = i; } } set[num] = max; used[max] = true; }}bool check() { int temp[1024]; for (int i=1; i<=n; i++) { memset(temp, 0, sizeof(temp)); int t = 0; for (int j=i+1; j<=n; j++) { if (g[set[i]][set[j]]) { t++; temp[t] = set[j]; } } for (int j=2; j<=t; j++) { if (!g[temp[j]][temp[1]]) return false; } } return true;}int main() { while (scanf("%d%d", &n, &m) == 2) { if (n == 0 && m == 0) break; memset(g, false, sizeof(g)); int a, b; for (int i=0; i<m; i++) { scanf("%d%d", &a, &b); g[a][b] = g[b][a] = true; } set[n] = 1; Relable(); if (check()) printf("Perfectn"); else printf("Imperfectn"); printf("n"); } return 0;}
