#include #include using namespace std; using namespace atcoder; #define REP(i,a,n) for(int i=(a); i<(int)(n); i++) #define rep(i,n) REP(i,0,n) #define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it) #define ALLOF(c) (c).begin(), (c).end() typedef long long ll; typedef unsigned long long ull; //using mint = modint1000000007; //using mint = modint998244353; int main(){ string S; cin >> S; if(S.size() == 1){ cout << S << endl; }else{ cout << "" << endl; } return 0; }