#include <iostream>#include <cstdio>#include <cstring>#include <cmath>#include <cstdlib>#include <algorithm>#include <vector>using namespace std;#define SZ(v) ((int)(v).size())const int maxn = 128;int g[maxn+5][maxn+5],vis[maxn+5][maxn+5],com[maxn+5][maxn+5];int n,m,ans;void clique(int com_cnt,int vis_cnt,int dep){ if(!com_cnt){ if(!vis_cnt) ans++; return; } for(int i=1;i<=vis_cnt;i++){ bool found=false; int t=vis[dep][i]; for(int j=1;j<=com_cnt;j++){ if(!g[t][com[dep][j]]){ found=true; break; } } if(!found) return; } for(int i=1;i<=com_cnt;i++){ int v=com[dep][i]; int t,t_com_cnt=0,t_vis_cnt=0; for(int j=i+1;j<=com_cnt;j++){ t=com[dep][j]; if(g[v][t]) com[dep+1][++t_com_cnt]=t; } for(int j=1;j<=vis_cnt;j++){ t=vis[dep][j]; if(g[v][t]) vis[dep+1][++t_vis_cnt]=t; } if(ans>1000) return; clique(t_com_cnt,t_vis_cnt,dep+1); vis[dep][++vis_cnt]=v; }}int main() { while(scanf("%d%d",&n,&m)==2){ memset(g,0,sizeof(g)); for(int i=1;i<=m;i++){ int u,v; scanf("%d%d",&u,&v); g[u][v]=g[v][u]=1; } ans=0; for(int i=1;i<=n;i++) com[1][i]=i; clique(n,0,1); if(ans>1000){ printf("Too many maximal sets of friends.n"); } else{ printf("%dn",ans); } } return 0;}
