/*************************************
* author: marvinthang *
* created: 08.05.2023 10:24:39 *
*************************************/
#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define left ___left
#define right ___right
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define MASK(i) (1LL << (i))
#define BIT(x, i) ((x) >> (i) & 1)
#define __builtin_popcount __builtin_popcountll
#define ALL(v) (v).begin(), (v).end()
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define REPD(i, n) for (int i = (n); i--; )
#define FOR(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define FORD(i, b, a) for (int i = (b), _a = (a); --i >= _a; )
#define FORE(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORDE(i, b, a) for (int i = (b), _a = (a); i >= _a; --i)
#define scan_op(...) istream & operator >> (istream &in, __VA_ARGS__ &u)
#define print_op(...) ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
#include "debug.h"
#else
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define DB(...) 23
#define db(...) 23
#define debug(...) 23
#endif
template <class U, class V> scan_op(pair <U, V>) { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>) { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>) { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")"; else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
const int MOD = 1e9 + 7;
namespace Mod {
inline void fasterLLDivMod(unsigned long long x, unsigned y, unsigned &out_d, unsigned &out_m) {
unsigned xh = (unsigned)(x >> 32), xl = (unsigned)x, d, m;
#ifdef __GNUC__
asm(
"divl %4 \n\t"
: "=a" (d), "=d" (m)
: "d" (xh), "a" (xl), "r" (y)
);
#else
__asm {
mov edx, dword ptr[xh];
mov eax, dword ptr[xl];
div dword ptr[y];
mov dword ptr[d], eax;
mov dword ptr[m], edx;
};
#endif
out_d = d; out_m = m;
}
template <class T> T invGeneral(T a, T b) {
a %= b;
if (!a) return b == 1 ? 0 : -1;
T x = invGeneral(b, a);
return x == -1 ? -1 : ((1 - 1LL * b * x) / a + b) % b;
}
template <int MOD>
struct ModInt {
unsigned int val;
ModInt(void): val(0) {}
ModInt(const long long &x) { *this = x; }
ModInt & normalize(const unsigned int &v) {
val = v >= MOD ? v - MOD : v;
return *this;
}
bool operator ! (void) { return !val; }
ModInt & operator = (const ModInt &x) { val = x.val; return *this; }
ModInt & operator = (const long long &x) { return normalize(x % MOD + MOD); }
ModInt operator - (void) { return ModInt(MOD - val); }
ModInt & operator += (const ModInt &other) { return normalize(val + other.val); }
ModInt & operator -= (const ModInt &other) { return normalize(val + MOD - other.val); }
ModInt & operator /= (const ModInt &other) { return *this *= other.inv(); }
ModInt & operator *= (const ModInt &other) {
unsigned dummy;
fasterLLDivMod((unsigned long long) val * other.val, MOD, dummy, val);
return *this;
}
ModInt operator + (const ModInt &other) const { return ModInt(*this) += other; }
ModInt operator - (const ModInt &other) const { return ModInt(*this) -= other; }
ModInt operator * (const ModInt &other) const { return ModInt(*this) *= other; }
ModInt operator / (const ModInt &other) const { return ModInt(*this) /= other; }
ModInt pow(long long n) const {
assert(n >= 0);
ModInt res = 1, a = *this;
for (; n; n >>= 1, a *= a) if (n & 1) res *= a;
return res;
}
ModInt inv(void) const {
int i = invGeneral((int) val, MOD);
assert(~i);
return i;
}
ModInt & operator ++ (void) { return *this += 1; }
ModInt & operator -- (void) { return *this -= 1; }
ModInt operator ++ (int) { ModInt old = *this; operator ++(); return old; }
ModInt operator -- (int) { ModInt old = *this; operator --(); return old; }
friend ModInt operator + (const long long &x, const ModInt &y) { return ModInt(x) + y; }
friend ModInt operator - (const long long &x, const ModInt &y) { return ModInt(x) - y; }
friend ModInt operator * (const long long &x, const ModInt &y) { return ModInt(x) * y; }
friend ModInt operator / (const long long &x, const ModInt &y) { return ModInt(x) / y; }
friend ostream & operator << (ostream &out, const ModInt &x) { return out << x.val; }
friend istream & operator >> (istream &in, ModInt &x) { long long a; in >> a; x = a; return in; }
bool operator < (const ModInt &other) const { return val < other.val; }
bool operator > (const ModInt &other) const { return val > other.val; }
bool operator <= (const ModInt &other) const { return val <= other.val; }
bool operator >= (const ModInt &other) const { return val >= other.val; }
bool operator == (const ModInt &other) const { return val == other.val; }
bool operator != (const ModInt &other) const { return val != other.val; }
explicit operator bool(void) const { return val; }
explicit operator int(void) const { return val; }
};
using Modular = ModInt <MOD>;
}
using namespace Mod;
// end of template
const int MAX = 1e5 + 5;
int N, H[MAX], W[MAX];
void init(void) {
cin >> N;
REP(i, N) cin >> H[i];
REP(i, N) cin >> W[i];
}
vector <int> add[MAX];
int lab[MAX];
bool active[MAX];
Modular sum_w[MAX];
Modular sum_pair;
int find(int u) {
return lab[u] < 0 ? u : lab[u] = find(lab[u]);
}
bool join(int u, int v) {
u = find(u); v = find(v);
if (u == v) return false;
if (lab[u] > lab[v]) swap(u, v);
sum_pair -= sum_w[u] * (sum_w[u] + 1) / 2;
sum_pair -= sum_w[v] * (sum_w[v] + 1) / 2;
sum_w[u] += sum_w[v];
sum_pair += sum_w[u] * (sum_w[u] + 1) / 2;
lab[u] += lab[v];
lab[v] = u;
return true;
}
void process(void) {
vector <int> height {0};
REP(i, N) {
height.push_back(H[i]);
sum_w[i] = W[i];
lab[i] = -1;
}
sort(ALL(height));
height.erase(unique(ALL(height)), height.end());
REP(i, N) add[lower_bound(ALL(height), H[i]) - height.begin()].push_back(i);
Modular res = 0;
FORD(i, height.size(), 1) {
for (int u: add[i]) {
sum_pair += sum_w[u] * (sum_w[u] + 1) / 2;
if (u && active[u - 1]) join(u, u - 1);
if (u + 1 < N && active[u + 1]) join(u, u + 1);
active[u] = true;
}
int l = height[i - 1] + 1;
int r = height[i];
res += 1LL * (r + l) * (r - l + 1) / 2 * sum_pair;
}
cout << res << '\n';
}
int main(void) {
ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
file("A");
init();
process();
cerr << "Time elapsed: " << TIME << " s.\n";
return (0^0);
}
