#include
#include
using namespace std;
int histogram(int arr[],int n){
int cur_area,max_area=0,extract;
stack s;
int i=1;
s.push(0);
while(i<n){
if(s.empty() or arr[i]>=arr[s.top()]){
s.push(i);
i++;
}else{
extract=s.top();
s.pop();
if(s.empty()){
cur_area = arr[extract]i;
}else{
cur_area = arr[extract](i-1-s.top());
}
max_area = max(max_area,cur_area);
}
}
while(!s.empty()){
extract=s.top();
s.pop();
if(s.empty()){
cur_area = arr[extract]i;
}else{
cur_area = arr[extract](i-1-s.top());
}
max_area = max(max_area,cur_area);
}
return max_area;
}
int main(){
int n;
cin>>n;
int arr[n];
for(int i=0;i<n;i++){
cin>>arr[i];
}
cout<<histogram(arr,n)<<endl;
return 0;
}