#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define nl '\n'
ld xisn(pair<int,int> l1, pair<int,int> l2){
auto [m1, c1] = l1;
auto [m2, c2] = l2;
return (ld)(c2 - c1)/(m1 - m2);
}
int yval(pair<int,int> l, int x){
auto [m, c] = l;
return m*x + c;
}
inline void solve(){
int n;
cin>>n;
int a[n];
for(int i=0; i<n; i++) cin>>a[i];
deque<pair<int,int>> dq;
int ldp = 0, mx = 0;
for(int i=0; i<n; i++){
mx = max(mx, a[i]);
pair<int,int> cur = {i, ldp};
while(dq.size() >= 2 and xisn(dq.back(), cur) <= xisn(dq.back(), dq[(int)dq.size()-2])) dq.pop_back();
dq.push_back(cur);
while(dq.size() >= 2 and yval(dq[0], mx) <= yval(dq[1], mx)) dq.pop_front();
ldp = yval(dq[0], mx) - n*mx;
}
cout<<-ldp;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);cout.tie(NULL);
int t = 1;
//cin>>t;
while(t--) solve();
return 0;
}
