• 没啥好说的，就是个模拟题。

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

string s;

void check(){
    int n =s.size();
    if(n>4){
        for (int i = 0; i < n; i ++ ){
            cout << s[i];
            if(i==3)cout<<"-";
        }
    }
    else{
        int x=10*(s[0]-'0')+s[1]-'0';
        if(x<22) {
            cout << "20";
              for (int i = 0; i < n; i ++ ){
                cout << s[i];
                if(i==1)cout<<"-";
            }
        }
        else{
             cout << "19";
              for (int i = 0; i < n; i ++ ){
                cout << s[i];
                if(i==1)cout<<"-";
            }   

        }
    }

}

int main()
{
    cin>>s;
    check();

    return 0;
}