import java.io.*;
import java.util.*;
public class Discharging {
static class Reader
{
final private int BUFFER_SIZE = 1 << 16;
private DataInputStream din;
private byte[] buffer;
private int bufferPointer, bytesRead;
public Reader()
{
din = new DataInputStream(System.in);
buffer = new byte[BUFFER_SIZE];
bufferPointer = bytesRead = 0;
}
public int nextInt() throws IOException
{
int ret = 0;
byte c = read();
while (c <= ' ')
c = read();
boolean neg = (c == '-');
if (neg)
c = read();
do
{
ret = ret * 10 + c - '0';
} while ((c = read()) >= '0' && c <= '9');
if (neg)
return -ret;
return ret;
}
public long nextLong() throws IOException
{
long ret = 0;
byte c = read();
while (c <= ' ')
c = read();
boolean neg = (c == '-');
if (neg)
c = read();
do {
ret = ret * 10 + c - '0';
}
while ((c = read()) >= '0' && c <= '9');
if (neg)
return -ret;
return ret;
}
private void fillBuffer() throws IOException
{
bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
if (bytesRead == -1)
buffer[0] = -1;
}
private byte read() throws IOException
{
if (bufferPointer == bytesRead)
fillBuffer();
return buffer[bufferPointer++];
}
}
public static Vector<Double> intersect = new Vector<Double>();
public static Vector<Long> grad = new Vector<Long>(),constant = new Vector<Long>();
static boolean cmp(int a,int b,long g,long ct) {
return (ct - constant.get(b))*(grad.get(a) - g) < (ct - constant.get(a))*(grad.get(b) - g);
}
public static double intersection(int a,long g,long ct){
return ((double)constant.get(a)-(double)ct)/((double)g-(double)grad.get(a));
}
public static void popHull(){
int a = constant.size()-1;
constant.remove(a);
grad.remove(a);
intersect.remove(a);
}
public static void pushHull(double a,long b,long c){
intersect.add(a);
grad.add(b);
constant.add(c);
}
public static void main(String[] args) throws IOException {
Reader reader = new Reader();
int N = reader.nextInt();
long[] T = new long[N+1];
for(int i = 1; i <= N; i++) {
T[i] = reader.nextLong();
}
Vector<Long> dp = new Vector<Long>();
dp.add(0L);
pushHull(2e9,0l,0l);
long curDpVal =0;
long curMax = 0;
int idx = 0;
for(int i = 1; i <= N; i++){
long curT = T[i];
if(curT >= curMax){
curMax = curT;
while(intersect.get(idx)<(double)curMax)idx++;
curDpVal = N*curMax + grad.get(idx) * curMax + constant.get(idx);
}
dp.add(curDpVal);
long g = -i;
long ct = dp.get(i);
while(intersect.size()-idx >= 2 && cmp(intersect.size()-2,intersect.size()-1,g,ct)){
popHull();
}
intersect.set(intersect.size()-1, intersection(intersect.size()-1,g,ct));
pushHull(2e9,g,ct);
}
System.out.print(dp.get(N));
// write code here
}
}
