int sum(int I, int K)
{
int retval = 0;
for(int i = I; i <=K; i++)
retval = retval + i;
return retval;
}

int sum2(int I, int K)
{
if (I == K)
return I;
else
return I + sum2(I+1, K);
}

int max1(int I, int K)
{
int revI = reverse(I);
int revK = reverse(K);
retval = max(revI, revK);
return reverse(retval);
}

int max(int revI, int revK)
{
if (revI % 10 > revK % 10)
return revI;
else if (revI % 10 < revK % 10)
return revK;
else // they are equal
return revI % 10 + 10 * max(revI/10, revK/10);
}