class Solution {
public:
    int countValidWords(string sentence) {
        vector<string> tokens = split(sentence);
        int ans=0;
        for (string item:tokens){
            bool flag = false;
            int cnt_ = 0; // -的个数
            int cntb = 0; // 标点的个数
            for (int i=0; i<item.length(); i++){                                
                if (item[i]=='!' || item[i]=='.' || item[i]==','){
                    if (i!=item.length()-1){
                        flag = true;
                        break;
                    }
                    cntb +=1;                    
                }
                else if (isdigit(item[i])){
                    flag = true;
                    break;
                }
                else if (item[i]=='-'){
                    if (i==0 || i==item.length()-1 || (!isalpha(item[i-1])) || (!isalpha(item[i+1]))){
                        flag = true;
                        break;
                    }
                    cnt_ +=1;
                }
            }
            if (flag){
                continue;
            }
            else if (cnt_>1 || cntb>1){
                continue;
            }
            cout<<item<<" ";
            ans +=1;
        }

        return ans;
    }
    vector<string> split(string astr){
        istringstream ass(astr);
        string out;
        vector<string> ans;
        while (ass>>out){
            ans.push_back(out);
        }
        return ans;
    }
};