#include <bits/stdc++.h>
using namespace std;

int main()
{
    string s1,s2,s3;
    //vector<string> a;
    while(getline(cin,s1))
    {
        if(s1=="START")
        {
            getline(cin,s2);
            for(int i=0;i<s2.size();i++)
            {
                if(s2[i]>='A'&&s2[i]<='Z')
                {
                    s2[i]=(s2[i]-'A'-5+26)%26+'A';
                }
            }
            //a.push_back(s2);
            cout<<s2<<endl;
            getline(cin,s3);
        }
        if(s1=="ENDOFINPUT")
            break;
    }
//    for(int i=0;i<a.size();i++)
//    {
//        cout<<a[i]<<endl;
//    }
    //return 0; 
} 

真的是要想尽办法减少时间开销，把getline(cin,s1)放到while循环里比较好