#include using namespace std; using ll=long long; #define rep2(i, a, n) for(int i = (a); i < (n); i++) #define rep(i, n) rep2(i,0,n) templatevoid flagfunc1(S &flag,T A,U B){flag?cout<>s; map map; rep(i,13)map[s[i]]++; char hoge; bool flag=false; for(auto itr=map.begin();itr!=map.end();++itr){ //cout<<"key="<first<<",val="<second<<"\n"; if(!flag&&itr->second==1){ hoge=itr->first; flag=true; }else if(itr->second>2){ break; } } flagfunc1(flag,hoge,"Impossible"); }