#include <iostream>

using namespace std;

int norocoase(int,int);

int main()
{
    int a,b;
    cin>>a;
    cin>>b;
    cout<<norocoase(a,b);
    return 0;
}

int norocoase(int a,int b){
    int i,j=1,nr=0,k;
    for(i=a;i<=b;i++){
        k=i;
        for(j=1;j<=i;j++){
            if(i%2==0) break;
            if(i*i==((j+k)*i)/2) {
                nr++;
                break;
            }else k++;
        }
    }
    return nr;
}