#include <stdio.h>
#include <ctype.h>

int main()
{
    int color;

    do
    {
        printf("\nEnter mode --> ");
        color = getchar();
        if (color == 10)
            continue;

        // clean buffer
        int c;
        while ((c = getchar()) != '\n' && c != EOF)
        {
        }

    } while (!isdigit(color) || (color != '1' && color != '0'));

    printf("\nCOLOR: %c\n", color);
}