#include<bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
using namespace std;
const int mxn=1e6+5;
const ll inf=1e18;
vector<ll> m,b;
ll f(int i, ll x) { return m[i] * x + b[i]; }
bool bad(int f1,int f2,int f3) {
return __int128(b[f3] - b[f1]) * (m[f1] - m[f2]) <= __int128(b[f2] - b[f1]) * (m[f1] - m[f3]);
}
void add(ll m_, ll b_) {
m.push_back(m_);
b.push_back(b_);
int sz = m.size();
while(sz >=3 && bad(sz-3,sz-2,sz-1)) {
m.erase(m.end() - 2);
b.erase(b.end() - 2);
sz--;
}
}
ll query(ll x) {
ll ans = inf;
int lo = 0;
int hi = m.size() - 1;
while(lo <= hi) {
int mid1 = lo + (hi - lo) / 3;
int mid2 = hi - (hi - hi) / 3;
ll v1 = f(mid1,x);
ll v2 = f(mid2,x);
if(v1 <= v2) {
ans = min(ans,v1);
hi = mid2 - 1;
} else {
ans = min(ans,v2);
lo = mid1 + 1;
}
}
return ans;
}
int main() {
int n;
cin>>n;
ll t[n+1];
for(int i = 1; i <= n; i++) cin>>t[i];
ll dp[n+1];
dp[0] = 0;
add(0,0);
ll cm = 0;
int lp = 1;
for(int i = 1; i <= n; i++) {
if(t[i] >= cm) {
cm = t[i];
for(; lp < i; lp++) {
add(-lp,dp[lp]);
}
}
dp[i] = query(cm) + cm * n;
}
cout<<dp[n]<<endl;
}
