#include using namespace std; #define ll long long #define FOR(i,n,m) for(int i=(n);i<(m);i++) #define REP(i,n) FOR(i,0,n) #define REPR(i,n) for(int i=(n);i>=0;i--) #define all(vec) vec.begin(),vec.end() using vi=vector; using vvi=vector; using vl=vector; using vvl=vector; using P=pair; using PP=pair; using vp=vector

; using vpp=vector; using vs=vector; #define fi first #define se second #define pb push_back templatebool chmax(T &a,const T &b){if(abool chmin(T &a,const T &b){if(a>b){a=b;return true;}return false;} const ll MOD=1000000007LL; const int INF=1<<30; const ll LINF=1LL<<60; int main(){ string st; cin>>st; int n=st.size(); if(st[0]!='1'){ cout<<"-1"<