#include<iostream>
#include<string>
#include<cctype>
using namespace std;
int main()
{
  string s,result=" ";
  int final;
  getline(cin,s);
  for(char c:s)
  {
      if(isdigital(c))
      {
          result+=c;
      }
  }
  if(result.empty())
  {
      cout<<-1<<endl;
  }
  else
  {
      final=stoi(result);
      cout<<final<<endl;
  }
  return 0;
}