include[HTML_REMOVED]
include[HTML_REMOVED]
include[HTML_REMOVED]
using namespace std;
int main()
{
int x, y, n = 0,i=1;
cin >> x >> y;
int c=0;
for ( i = 1; i < abs(y - x); i++)
{
if (x >= y)
c = y + i;
else
c = x + i;
if (abs(c) % 2 == 1)
{
n = n + c;
}
}
cout << n << endl;
return 0;
}