>//输入E
>    A
>   ABA
>  ABCBA   
> ABCDCBA
>ABCDEDCBA

#include<stdio.h>
#include<math.h>

int main(void)
{
	int line, line_all, row_blank, row_plus, row_minus;
	char ch;
	
	scanf_s("%c", &ch);
	line_all = ch - 'A' + 1;
	for (line=1; line <= line_all; line++)
	{
		for (row_blank = 0; row_blank < line_all - line; row_blank++)
			printf("%c", ' ');
		for (row_plus = 0; row_plus < line; row_plus++)
			printf("%c", 'A' + row_plus);
		for (row_minus = row_plus - 2; row_minus >= 0; row_minus--)
			printf("%c", 'A' + row_minus);
		printf("\n");
	}

	getchar();
	return 0;
}