1725.cpp

#include <bits/stdc++.h>
#define fastio ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)

#define ll long long
using namespace std;

const ll INF = 1e9 + 7;
const ll DIV = 987654321;

int n;
stack<pair<int,int>> st;

int main()
{
    fastio;
    cin >>n;
    int ans=0;
    st.push({-1, -1});
    for(int i=0;i<n;i++){
        int a;
        cin >> a;
        while(1){
            auto[x,h] = st.top();
            if(h < a){
                break;
            }
            st.pop();
            auto[y, z]=st.top();
            ans=max(ans, (i-y-1)*h);
        }
        st.push({i,a});
    }
    while(st.size() > 1){
        auto[x,h]=st.top();
        st.pop();
        auto[y, z]=st.top();
        ans=max(ans, (n-y-1)*h);
    }
    cout << ans;
    return 0;
}