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

char ToAscii(int val)
{
    return (val >= 0 && val <= 'Z' - 'A')? val + 'A': ' ';
}

int main(void)
{
    int n;
    int i, j;
    printf("Please indicate the number of stairs.\n>");
    scanf("%d", &n);

    printf("\n");
    printf("i = [%d, %d]\n", 1 - n, n - 1);
    printf("j = [%d, %d]\n", 1 - n, n - 1);

    printf("\n");
    printf("f(i, j) = i + j\n");

    for(i = 1 - n; i < n; ++i)
    {
        for(j = 1 - n; j < n; ++j)
        {
            int val = i + j;
            printf("%c", ToAscii(val));
        }
        printf("\n");
    }

    printf("\n");
    printf("f(i, j) = abs(i) + abs(j)\n");

    for(i = 1 - n; i < n; ++i)
    {
        for(j = 1 - n; j < n; ++j)
        {
            int val = abs(i) + abs(j);
            printf("%c", ToAscii(val));
        }
        printf("\n");
    }

    printf("\n");
    printf("f(i, j) = %d - (abs(i) + abs(j))\n", n - 1);

    for(i = 1 - n; i < n; ++i)
    {
        for(j = 1 - n; j < n; ++j)
        {
            int val = n - 1 - abs(i) - abs(j);
            printf("%c", ToAscii(val));
        }
        printf("\n");
    }
    return 0;
}