4850: 【GESP2506二级】幂和数

#include <iostream>
using namespace std;
int main()
{
    int l, r, a, b, n, cnt = 0;
    cin >> l >> r;
    a = 1;
    while(a<=r)
    {
        b = a;
        while(b<=r)
        {
            n = a+b;
            if(n>=l && n<=r) cnt++;
            b *= 2;
        }
        a *= 2;
    }
    cout << cnt <<endl;
    return 0;
}