L = [1,2,7] S = [1,3,10] Mod = 1000000007 n = int(input()) if n <=2: print(L[n]) else: for i in range(3,n+1): L.append((2*L[i-1] + 3*L[i-2] + S[i-3]*2) % Mod) S.append(S[-1]+L[-1]) print(L[-1])