#pragma GCC optimize("Ofast")
#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <queue>
#include <cstdio>
#include <ctime>
#include <assert.h>
#include <chrono>
#include <random>
#include <numeric>
#include <set>
#include <deque>
#include <stack>
#include <sstream>
#include <utility>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <tuple>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
    return (ull)rng() % B;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n; cin >> n;
    vector<int> p(n);
    ll res = 0;
    vector<ll> u(n);
    for(int i=0;i<n;i++){
        cin >> p[i];
        u[p[i]-1] = (i+1);
    }
    ll sum = u[0];
    for(int i=1;i<n;i++){
        res = max(res,sum-u[i]);
        sum += u[i];
    }
    cout << res << endl;
}