string getSentence(production p, map<string, Definition>& grammar){
  string result;
  for (Production::iterator curr = p.begin(); curr != p.end(); ++curr) {
    if(curr!='<'){
      result+=curr;
    }else{
      string prod;
      while(curr!='>'){
	++curr;
        prod+=curr;
      }
      result+=getSentence(grammar.get(prod).getRandomProduction(), grammar);
    }
  }
  return result;
}
void formSentence(map<string, Definition>& grammar){
  production p =  grammar.get("<start>").getRandomProduction();
  for(int i=0; i < 3; i++) cout << getSentence(p,grammar) << endl;