#include <iostream> #include <cctype> using namespace std; int main() { char start; cin >> start; int n = start - 'A' + 1; for (int i = 0; i < n; i++) { // 打印前导空格 for (int j = 0; j < i; j++) { cout << " "; } // 打印递减字母部分 for (char c = start - i; c >= 'A'; c--) { cout << c; } // 打印递增字母部分 for (char c = 'B'; c <= start - i; c++) { cout << c; } cout << endl; } return 0; }