#include using namespace std; #define all(a)a.begin(),a.end() using ll=long long; const int INF = 1<<30; const ll INFll =1LL<<62; const int mod= int(1e9)+7; //const int mod=998244353; using P = pair; using Pll = pair; using ld=long double; int main() { string s;cin >>s; reverse(all(s)); int k=(s[0]-'0'); if(s.size()==1){ if(k==4){ cout <<-1<