#include <bits/stdc++.h>
using namespace std;
#define int long long
const int inf = 1e15;
const int N = 1502;
using ll = long long;
ll eval(array<ll, 2> a, ll x) {
return a[0]*x + a[1];
}
struct LiChao {
struct Node {
Node *l, *r;
array<ll, 2> f;
Node() : l(0), r(0), f{0, -(1ll<<62)} {}
};
deque<Node> buf;
template<class... Args>
Node *newnode(Args... args) {
return &buf.emplace_back(args...);
}
void update(Node *&v, ll l, ll r, array<ll, 2> f) {
if(!v) {
v = newnode(), v->f = f;
return;
}
ll mid = l + (r-l)/2;
if(eval(f, mid) < eval(v->f, mid)) swap(f, v->f);
if(l == r) return;
if(eval(f, l) < eval(v->f, l))
update(v->l, l, mid, f);
else
update(v->r, mid+1, r, f);
}
ll query(Node *v, ll l, ll r, ll x) {
if(!v) return (1ll<<62);
ll mid = l + (r-l)/2;
return min(eval(v->f, x),
x <= mid ? query(v->l, l, mid, x) : query(v->r, mid+1, r, x));
}
void update(array<ll, 2> f) {
update(root, -(n-1), n-1, f);
}
ll query(ll x) {
return query(root, -(n-1), n-1, x);
}
ll n;
Node *root;
LiChao(ll _n) : n(_n), root(0) {}
};
signed main() {
std::ios::sync_with_stdio(0);
std::cout.tie(0);
std::cin.tie(0);
int n; cin >> n;
vector<int> a(n + 1), dp(n + 1);
for(int i = 1; i <= n; i++) cin >> a[i];
LiChao cht(1e9 + 3);
dp[1] = a[1] * n;
cht.update({n, 0}); //querying all n at one time
int mx = a[1];
for(int i = 2; i <= n; i++) {
mx = max(mx, a[i]);
cht.update({n - i + 1, dp[i - 1]});
dp[i] = cht.query(mx);
//we can qry for mx cuz the x coordinate has to be atleast mx (all under same time mx)
}
cout << dp[n] << '\n';
return 0;
}
