#include <stdio.h>
#include <stdlib.h>

#define MASK(msb, lsb) ( (((unsigned)1<<((msb)-(lsb)+1))-1) << (lsb) )

int main(int argc, char **argv) {
	unsigned a,b;

	if(argc<=1) {
		fprintf(stderr, "usage: %s <msb> <lsb>\n", argv[0]);
		return 1;
	}

	if(argc>1) {
		a=strtoul(argv[1], 0, 0);
	} else {
		a=0;
	}

	if(argc==3) {
		b=strtoul(argv[2], 0, 0);
	} else {
		b=a;
	}

	printf("0x%08x\n", MASK(a,b));
	return 0;
}