#include using namespace std; //#include // using namespace boost::multiprecision; // using cint = cpp_int; //#pragma GCC optimize("", on) //#pragma GCC optimization_level 3 //#define min(...) min({...}) //#define max(...) max({...}) // Define using ll = long long; using ull = unsigned long long; using ld = long double; const ll MOD = 1e9 + 7; const ll INF = LONG_MAX; const ull MAX = ULONG_MAX; #define mp make_pair #define pb push_back #define eb emplace_back #define x first #define y second #define endl '\n' #define space ' ' #define def inline auto #define func inline constexpr ll #define run __attribute__((constructor)) def _ #define all(v) begin(v), end(v) #define input(a) scanf("%lld", &(a)) #define print(a) printf("%lld\n", (a)) // Debug #define debug(...) \ { \ cerr << __LINE__ << ": " << #__VA_ARGS__ << " = "; \ for (auto &&X : {__VA_ARGS__}) cerr << "[" << X << "] "; \ cerr << endl; \ } #define dump(a, h, w) \ { \ cerr << __LINE__ << ": " << #a << " = [" << endl; \ rep(i, h) { \ rep(j, w) cerr << a[i][j] << space; \ cerr << endl; \ } \ cerr << "]" << endl; \ } #define vdump(a, n) \ { \ cerr << __LINE__ << ": " << #a << " = ["; \ rep(i, n) if (i) cerr << space << a[i]; \ else cerr << a[i]; \ cerr << "]" << endl; \ } // Loop #define inc(i, a, n) for (ll i = (a), _##i = (n); i <= _##i; ++i) #define dec(i, a, n) for (ll i = (a), _##i = (n); i >= _##i; --i) #define each(i, a) for (auto &&i : a) #define rep(i, n) inc(i, 0, n - 1) #define loop() for (;;) // Stream #define fout(n) cout << fixed << setprecision(n) #define fasten cin.tie(0), ios::sync_with_stdio(0) // Speed run() { fasten, fout(10); } #pragma GCC optimize("O3") #pragma GCC target("avx") // Math func gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; } func lcm(ll a, ll b) { return a * b / gcd(a, b); } func sign(ll a) { return a ? abs(a) / a : 0; } def in() { ll A; cin >> A; return A; } signed main() { ll N, S = 0, A[100000], B[100000]; cin >> N; N++; rep(i, N) cin >> A[i]; rep(i, N) cin >> B[i]; rep(i, N - 1) B[i + 1] += B[i], B[i + 1] %= MOD; rep(i, N) S += A[i] * B[N - i - 1], S %= MOD; cout << S << endl; } // for compilation: g++ -Ofast -march=native -o _ _.cpp -std=c++17