#include <bits/stdc++.h>
using namespace std;

long long n, p, m = 0, v = 0;
long long u[200001];

int main(){
    cin >> n;
        
    for(long long i = 0; i < n; i++){
        cin >> p;
        u[p] = i + 1;
    }
    
    for(long long i = 1; i < n; i++){
        v = v + u[i];
        m = max(m, v - u[i + 1]);
    }

    cout << m << endl;
}