int main()
{
//對函數f(x)=x^2+x+1;
double s,t;
double EPS=1.0e-3;
double ans=0;
double i;
while(scanf("%lf%lf",&s,&t)!=EOF)
for(i=s;i<t+1.0e-8;i+=EPS)
ans+=i*i+i+1;
}
printf("%lf\n",ans);
return 0;