include [HTML_REMOVED]
include [HTML_REMOVED]
include [HTML_REMOVED]
using namespace std;
int main()
{
int x,y;
cin >> x >> y;
if(x>y) swap(x,y);
int sum = 0;
for(int a=x+1;a<y;a=a+1){
if(a%2!=0){
sum+=a;
}
}
cout << sum;
return 0;
}