void do_bf(unsigned long sum, unsigned long mult, void (*callback)(unsigned char, unsigned char, unsigned char, unsigned char))
{
	int a, b, c, d;
	unsigned long s0, s1, s2, s3;
	unsigned long m0, m1, m2, m3;

	s0 = 0;
	m0 = 1;
	for (a=0 ; a<256 ; a++) {
		s1 = s0 + a;
		m1 = m0 * a;
		for (b=0 ; b<256 ; b++) {
			s2 = s1 + b;
			m2 = m1 * b;
			for (c=0 ; c<256 ; c++) {
				s3 = s2 + c;
				m3 = m2 * c;
				
				d = sum - s3;
				if (d > 255)
					continue;

				if (m3 * d == mult)
					callback(a, b, c, d);
			}
		}
	}
}

#ifndef BFLIB
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define chr(x) (((x) < 0x7f) && ((x) >= 0x20) ? x : '.')
void mycb(unsigned char a, unsigned char b, unsigned char c, unsigned char d)
{
	if ((d >= c) && (c >= b) && (b >= a))
		printf("Solution: %x (%c)  %x (%c)  %x (%c)  %x (%c)\n", a, chr(a), b, chr(b), c, chr(c), d, chr(d));
}

int main(int argc, char **argv)
{
	unsigned long sum, mult;
	unsigned char *ptr;
	
	if (argc < 2)
		_exit(1);

	ptr = argv[1];
	while (*ptr != '-')
		ptr++;
	
	sum = 0;
	while (*++ptr != '-') {
		sum *= 10;
		sum += *ptr - '0';
	}

	mult = 0;
	while (*++ptr != '-') {
		mult *= 10;
		mult += *ptr - '0';
	}
	
	do_bf(sum, mult, mycb);

	return 0;
}
#endif