#include #include #include using namespace std; //Strongly Connected Components #include struct SCC{ int n; vectorcomp,order; vectorused; vector >G,RG; SCC(int _n=0):n(_n),comp(_n,-1),used(_n,false),G(_n),RG(_n){} void add_edge(int from,int to) { G[from].push_back(to); RG[to].push_back(from); } void copy(const vector >&H) { for(int i=0;i=0;i--)if(comp[order[i]]==-1)rdfs(order[i],cnt++); return cnt; } int build(vector >&H) { int ret=build(); H.assign(ret,vector()); for(int i=0;ione[52],two[52][52]; string s[1<<17]; main() { cin>>N; for(int i=0;i>s[i]; int tr=i*2,fa=i*2+1; one[id(s[i][0])].push_back(tr); two[id(s[i][1])][id(s[i][2])].push_back(tr); two[id(s[i][0])][id(s[i][1])].push_back(fa); one[id(s[i][2])].push_back(fa); } SCC P(N*2); for(int i=0;i<52;i++) { if(one[i].size()>3000) { cout<<"Impossible"<3000) { cout<<"Impossible"<P[i*2+1]) { cout<