#!/usr/bin/env python3 # %% import sys read = sys.stdin.buffer.read readline = sys.stdin.buffer.readline readlines = sys.stdin.buffer.readlines # %% import numpy as np # %% MOD = 10 ** 9 + 7 # %% def cumprod(A, MOD=MOD): L = len(A) Lsq = int(L**.5 + 1) A = np.resize(A, Lsq**2).reshape(Lsq, Lsq) for n in range(1, Lsq): A[:, n] *= A[:, n - 1] A[:, n] %= MOD for n in range(1, Lsq): A[n] *= A[n - 1, -1] A[n] %= MOD return A.ravel()[:L] def make_fact(U, MOD=MOD): x = np.arange(U, dtype=np.int64) x[0] = 1 fact = cumprod(x, MOD) x = np.arange(U, 0, -1, dtype=np.int64) x[0] = pow(int(fact[-1]), MOD - 2, MOD) fact_inv = cumprod(x, MOD)[::-1] fact.flags.writeable = False fact_inv.flags.writeable = False return fact, fact_inv # %% D, L, R, K = map(int, read().split()) # %% DL = L.bit_length() DR = R.bit_length() if DL > DR: DL, DR = DL, DR lca_dep, r = divmod((DL + DR - K), 2) if lca_dep < 0 or lca_dep > L or r: print(0) exit() # %% K, DL, DR, lca_dep if lca_dep == DL: R_cand = 2 ** (DR - DL) else: R_cand = 2 ** (DR - lca_dep - 1) # %% fact, fact_inv = make_fact(2 ** 20) total = 1 for n in range(1, D + 1): total *= fact[2 ** (n - 1)] total %= MOD total *= R_cand total %= MOD d = pow(2, DR - 1, MOD) if DL == DR: d -= 1 total *= pow(d, MOD - 2, MOD) total %= MOD print(total)