// May this submission get accepted! #pragma GCC optimize ("O3") #pragma GCC target ("tune=native") #pragma GCC target ("avx") #include // 汎用マクロ #define ALL_OF(x) (x).begin(), (x).end() #define REP(i,n) for (long long i=0, i##_len=(n); i=i##_end; i--) #define STEP(i, is, ie, step) for (long long i=(is), i##_end=(ie), i##_step = (step); i<=i##_end; i+=i##_step) #define UNIQUE(v) do { sort((v).begin(), (v).end()); (v).erase(unique((v).begin(), (v).end()), (v).end()); } while (false) template bool chmax(T &a, const T &b) {if (a < b) {a = b; return true;} return false; } template bool chmin(T &a, const T &b) {if (a > b) {a = b; return true;} return false; } #define INF 0x7FFFFFFF #define LINF 0x7FFFFFFFFFFFFFFFLL #define Yes(q) ((q) ? "Yes" : "No") #define YES(q) ((q) ? "YES" : "NO") #define Possible(q) ((q) ? "Possible" : "Impossible") #define POSSIBLE(q) ((q) ? "POSSIBLE" : "IMPOSSIBLE") #define DUMP(q) cerr << "[DEBUG] " #q ": " << (q) << " at " __FILE__ ":" << __LINE__ << endl #define DUMPALL(q) do { cerr << "[DEBUG] " #q ": ["; REP(i, (q).size()) { cerr << (q)[i] << (i == i_len-1 ? "" : ", "); } cerr << "] at " __FILE__ ":" << __LINE__ << endl; } while (false) template T gcd(T a, T b) { if (a < b) std::swap(a, b); while (b) std::swap(a %= b, b); return a; } template T lcm(const T a, const T b) { return a / gcd(a, b) * b; } // gcc拡張マクロ #define popcount __builtin_popcount #define popcountll __builtin_popcountll // エイリアス #define DANCE_ long #define ROBOT_ unsigned #define HUMAN_ signed #define CHOKUDAI_ const using ll = DANCE_ HUMAN_ DANCE_; using ull = DANCE_ ROBOT_ DANCE_; using cll = DANCE_ DANCE_ CHOKUDAI_; using ld = long double; using namespace std; // モジュール // 剰余演算 constexpr ll pdiv = 1000000007LL; // 10^9+7 ll powll(ll a, ll n) { ll result = 1; ll base = a; ll mask = 1; while (mask <= n) { if (n & mask) (result *= base) %= pdiv; mask <<= 1; (base *= base) %= pdiv; } return result; } inline ll invll(ll a) { return powll(a, pdiv-2); } vector fac_cache = {1}, invfac_cache = {1}; void make_fac_cache(ll a) { ll old_max = fac_cache.size() - 1; if (a > old_max) { fac_cache .resize(a+1); invfac_cache.resize(a+1); for (ll i = old_max + 1; i <= a; i++) { fac_cache[i] = fac_cache[i-1] * i % pdiv; } invfac_cache[a] = invll(fac_cache[a]); for (ll i = a-1; i > old_max; i--) { invfac_cache[i] = invfac_cache[i+1] * (i + 1) % pdiv; } } } inline ll facll(ll a) { make_fac_cache(a); return fac_cache[a]; } inline ll invfacll(ll a) { make_fac_cache(a); return invfac_cache[a]; } inline bool isoutll(ll n, ll r) { return n < 0 || r < 0 || n < r; } inline ll nPr(ll n, ll r) { return isoutll(n, r) ? 0 : facll(n) * invfacll(n-r) % pdiv; } inline ll nCr(ll n, ll r) { return isoutll(n, r) ? 0 : facll(n) * invfacll(n-r) % pdiv * invfacll(r) % pdiv; } inline ll nHr(ll n, ll r) { return nCr(n+r-1, r); } // 処理内容 int main() { // インタラクティブ問題では除去した方がいいかも ios::sync_with_stdio(false); cin.tie(nullptr); ll d, l, r, k; cin >> d >> l >> r >> k; ll ld = 0, rd = 0; while (l > 1) { l /= 2; ld++; } while (r > 1) { r /= 2; rd++; } if ((k + rd + ld) % 2) { cout << 0 << endl; return 0; } ll lcad = (ld + rd - k) / 2; if (lcad < 0 || rd - lcad == 0) { cout << 0 << endl; return 0; } make_fac_cache(1LL << (d-1)); ll ans = 1; REP(dc, d) { if (dc == rd) { ll plen = rd - lcad; if (ld != rd) { ans *= facll((1LL << dc) - 1); ans %= pdiv; if (lcad == ld) { ans *= 1LL << plen; } else { ans *= 1LL << (plen-1); } ans %= pdiv; } else { ans *= 1LL << dc; ans %= pdiv; ans *= facll((1LL << dc) - 2); ans %= pdiv; ans *= 1LL << (plen-1); ans %= pdiv; } } else { (ans *= facll(1LL << dc)) %= pdiv; } } DUMP(lcad); DUMP(ld); DUMP(rd); cout << ans << endl; }