#include<iostream> // 流输入输出 ，cin cout 
using namespace std; //命名空间 
int main(){ // 主函数 
    cout<<"ABCDEFGHIJKLMNOPQR"<<endl;
    cout<<"BABCDEFGHIJKLMNOPQ"<<endl;
    cout<<"CBABCDEFGHIJKLMNOP"<<endl;
    cout<<"DCBABCDEFGHIJKLMNO"<<endl;
    cout<<"EDCBABCDEFGHIJKLMN"<<endl;
    cout<<"FEDCBABCDEFGHIJKLM"<<endl;
    cout<<"GFEDCBABCDEFGHIJKL"<<endl;
    cout<<"HGFEDCBABCDEFGHIJK"<<endl;
    cout<<"IHGFEDCBABCDEFGHIJ"<<endl;
    cout<<"JIHGFEDCBABCDEFGHI"<<endl;
	return 0; // 返回值 
}