#include<bits/stdc++.h>
using namespace std;
using i64 = long long;
#define int i64
#define vi vector<int>
#define vvi vector<vi>
#define vb vector<bool>
#define pii pair<int, int>
#define fi first
#define se second
#define sz(x) (int)(x).size()
const long double EPS = 1e-12;
struct Line{
int m, c;
Line(int m, int c) : m(m), c(c) {}
Line() : Line(0, 0) {}
inline int eval(int x){
return m * x + c;
}
inline long double x_int(Line &other){
return (long double)(c - other.c) / (other.m - m + EPS);
}
};
inline void solve(){
int n;
cin >> n;
vi a(n), pref(n);
for(int &i : a){
cin >> i;
}
pref.front() = a.front();
for(int i = 1; i < n; i++){
pref[i] = max(pref[i - 1], a[i]);
}
// in an optimal grouping, pref[i] must belongs to the last group.
// dp[i] = contribution of grouping from 1 to i to the final grouping
deque<Line> dq;
vi dp(n);
dp[0] = n * a[0];
dq.emplace_front(n, 0);
Line line;
for(int i = 1; i < n; i++){
while(sz(dq) >= 2 && dq.back().eval(pref[i]) >= dq[sz(dq) - 2].eval(pref[i])){
dq.pop_back();
}
dp[i] = dq.back().eval(pref[i]);
line = {n - i, (i ? dp[i - 1] : 0)};
while(sz(dq) >= 2 && line.x_int(dq.front()) <= dq.front().x_int(dq[1])){
dq.pop_front();
}
dq.emplace_front(line);
}
cout << dp[n - 1] << "\n";
return;
}
signed main(){
ios_base::sync_with_stdio(false); cin.tie(0);
int t = 1;
//cin >> t;
while(t--){
solve();
}
return 0;
}
