打印

#include<bits/stdc++.h>
using namespace std;
int main(){printf("ABCDEFGHIJKLMNOPQR\nBABCDEFGHIJKLMNOPQ\nCBABCDEFGHIJKLMNOP\nDCBABCDEFGHIJKLMNO\nEDCBABCDEFGHIJKLMN\nFEDCBABCDEFGHIJKLM\nGFEDCBABCDEFGHIJKL\nHGFEDCBABCDEFGHIJK\nIHGFEDCBABCDEFGHIJ\nJIHGFEDCBABCDEFGHI");return 0;}