#include <iostream>

using namespace std;
int main() {
    while (true) {
        string command;
        cout << ">>>";
        getline(cin, command);

        if (command == "list"){
            cout << "list" <<endl;
        }
        else if (command == "exit") {
            return 0;
        }
        else {
            printf("未知的指令\"%s\",请使用\"help\"获取更多帮助\n",command.c_str());
        }
    }
}