#include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long ll; typedef vector vec; typedef vector mat; ll K; ll MOD = 1000000007; mat mul(mat &A, mat &B) { mat C(A.size(), vec(B[0].size())); for (int i = 0; i < A.size(); ++i) { for (int k = 0; k < B.size(); ++k) { for (int j = 0; j < B[0].size(); ++j) { C[i][j] = (C[i][j] + A[i][k] * B[k][j]) % MOD; } } } return C; } // 行列の累乗 mat pow(mat A, ll n) { mat B(A.size(), vec(A.size())); for (int i = 0; i < A.size(); ++i) { B[i][i] = 1; } while (n > 0) { if (n & 1) B = mul(B, A); A = mul(A, A); n >>= 1; } return B; } int main() { cin >> K; mat M(4); ll a; for (int i = 0; i < 4; ++i) { for (int j = 0; j < 4; ++j) { if (i == j) { M[i].push_back(0); } else { M[i].push_back(1); } } } mat C = pow(M, K); cout << C[0][0] << endl; return 0; }