unsigned f(unsigned n, unsigned k) {
    if (n < 2) {
        return k <= 1 & (n != 0) & ~k;
    }

    unsigned res;
    unsigned m = -1, r = 0;

    unsigned i;
    unsigned Cn, Ck, Cres;

    i = n;
    while (i != 0) {
        i >>= 1;
        m ++;
    }

    i = 1 << (m - 1);
    while ((n & i) == 0 && i != 0) {
        i >>= 1;
        r ++;
    }

    Cn = m;
    Ck = k + 1;
    if (Ck > Cn) {
        goto M1;
    } else if (Ck * 2 > n) {
        Ck = Cn - Ck;
    }
    if (Ck == 0) {
        res = 1;
        goto M1;
    }
    res = Cn;
    i = 2;
    while (i <= Ck) {
        res *= (Cn - i + 1);
        res /= i;
        i ++;
    }

M1:
    n ^= (1 << m);
    k -= r;
    m -= (r + 1);
    r = 0;

    i = 1 << (m - 1);
    while ((n & i) == 0 && i != 0) {
        i >>= 1;
        r ++;
    }

    while (1) {
        if (n == 0) {
            return res + (k == 0);
        }
        if (k == 0) {
            return res + (n == (1 << (m + 1)) - 1);
        }

        Cn = m;
        Ck = k - 1;
        if (Ck > Cn) {
            goto M;
        } else if (Ck * 2 > n) {
            Ck = Cn - Ck;
        }
        if (Ck == 0) {
            res += 1;
            goto M;
        }
        Cres = Cn;
        i = 2;
        while (i <= Ck) {
            Cres *= (Cn - i + 1);
            Cres /= i;
            i ++;
        }
        res += Cres;
M:
        n ^= (1 << m);
        k -= r;
        m -= (r + 1);
        r = 0;
        i = 1 << (m - 1);
        while ((n & i) == 0 && i != 0) {
            i >>= 1;
            r ++;
        }
    }
}