int
poly_size()
{
    int     i   = 0;
    int     j   = 0;
    int     min = STACK_SIZE;
    char    c   = 0;
    char    top = 0;

    char polybuf[STACK_SIZE];

    fgets(polybuf, STACK_SIZE, stdin);
    for (i = 'A'; i <= 'Z'; i++) {
        struct stack *s = create_stack(STACK_SIZE);
        while ((c = polybuf[j++]) != '\0') {
            if (c == i || c == i + 32 || c == '\n')
                continue;
            top = pop(s);
            if (!match(c, top)) {
                push(s, top);
                push(s, c);
            }
        }
        min = (s->top < min ? s->top : min);
        j = 0;
    }
    return min;
}