// editor3
#include<iostream>
using namespace std;
int main(){
  string s;
  cin>>s;
  string relult="";
 if(s.length()>=1&& s.length()<=100){
  for (int i=0;i<s.length();i++){
      if(isdigit(s[i])){
          
      }
  }
if(result.length()==0){
    cout<<-1;
    
}else{
    int f=stoil(result);
    cout<<f;
}
return 0;
}