#include <bits/stdc++.h>
#define int int64_t
using namespace std;
#define endl '\n'
const int nmax = 1e5 + 5, mod = 1e9 + 7;
int n, h[nmax], w[nmax], wp[nmax];
int st[4 * nmax], res, st_1[4 * nmax], lz[4 * nmax];
void lazy(int id)
{
if(lz[id] != 0)
{
st_1[id << 1] = max({st_1[id << 1], lz[id], lz[id << 1]});
lz[id << 1] = max(lz[id << 1], lz[id]);
st_1[id << 1 | 1] = max({st_1[id << 1 | 1], lz[id], lz[id << 1 | 1]});
lz[id << 1 | 1] = max(lz[id << 1 | 1], lz[id]);
lz[id] = 0;
}
}
void update_1(int id, int l, int r, int u, int v, int val)
{
if(l > v || r < u)
return;
if(l >= u && r <= v)
{
st_1[id] = max(st_1[id], val);
lz[id] = val;
return;
}
int mid = (l + r) >> 1;
lazy(id);
update_1(id << 1, l, mid, u, v, val);
update_1(id << 1 | 1, mid + 1, r, u, v, val);
st_1[id] = max(st_1[id << 1], st_1[id << 1 | 1]);
}
int get_1(int id, int l, int r, int pos)
{
if(pos > r || pos < l)
return 0;
if(l == r)
return st_1[id];
int mid = (l + r) >> 1;
lazy(id);
return max(get_1(id << 1, l, mid, pos), get_1(id << 1 | 1, mid + 1, r, pos));
}
void update(int id, int l, int r, int pos, int val)
{
if(r < pos || l > pos)
return;
if(l == r)
{
st[id] = val;
return;
}
int mid = (l + r) >> 1;
update(id << 1, l, mid, pos, val);
update(id << 1 | 1, mid + 1, r, pos, val);
st[id] = min(st[id << 1], st[id << 1 | 1]);
}
int get_r(int id, int l, int r, int pos, int val)
{
if(st[id] >= val || r < pos)
return n + 1;
if(l == r)
return l;
int mid = (l + r) >> 1;
int kq = get_r(id << 1, l, mid, pos, val);
if(kq == n + 1)
kq = get_r(id << 1 | 1, mid + 1, r, pos, val);
return kq;
}
int get_l(int id, int l, int r, int pos, int val)
{
if(st[id] >= val || pos < l)
return 0;
if(l == r)
return l;
int mid = (l + r) >> 1;
int kq = get_l(id << 1 | 1, mid + 1, r, pos, val);
if(kq == 0)
kq = get_l(id << 1, l, mid, pos, val);
return kq;
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
freopen("FENCE.INP", "r", stdin);
freopen("FENCE.OUT", "w", stdout);
cin>>n;
for(int i=1; i<=n; i++)
{
cin>>h[i];
update(1, 1, n, i, h[i]);
}
for(int i=1; i<=n; i++)
{
cin>>w[i];
wp[i] = wp[i-1] + w[i];
}
for(int i=1, l, r, tmp_1, tmp_2, ck; i<=n; i++)
{
l = get_l(1, 1, n, i, h[i]) + 1;
r = get_r(1, 1, n, i, h[i]) - 1;
tmp_1 = (wp[r] - wp[l-1]) * (wp[r] - wp[l-1] + 1) >> 1;
tmp_2 = tmp_1 * (h[i] * (h[i] + 1) >> 1);
tmp_2 -= tmp_1 * get_1(1, 1, n, i);
res += tmp_2;
update_1(1, 1, n, l, r, h[i]);
}
cout<<res;
}
