#include <bits/stdc++.h>

using namespace std;

//macro-----------------------------------------------------------------------------------------
#define rep(i,a,b) for(int i=a;i<b;i++)
#define revrep(i,a,b) for(int i=a;i>b;i--)
#define int long long

//constant--------------------------------------------------------------------------------------
const int inf = 100100100100000;
const int mod = 1000000007;
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
const string alpha = "abcdefghijklmnopqrstuvwxyz";

//general_method--------------------------------------------------------------------------------
vector<int> cs(vector<int> arr){vector<int> ret = arr;rep(i,1,arr.size()){ret[i] += ret[i-1];}return ret;}
int ceil(int a, int b){if(a%b == 0) return a/b;else return a/b + 1;}
int digitlen(int i){int t = i;int count = 0;while(t){count += 1;t /= 10;}return count;}
int gcd(int m, int n){if((0== m)||(0 == n))return 0;while(m != n){if(m > n)m = m - n;else n = n - m;}return m;}
int lcm(int n, int m){return n*m/gcd(n,m);}

//io_method-------------------------------------------------------------------------------------
int input(){int tmp;cin >> tmp;return tmp;}
string raw_input(){string tmp;cin >> tmp;return tmp;}
string readline(){string s;getline(cin, s);return s;}

template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i) o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}

//main------------------------------------------------------------------------------------------
vector<int> arr;

bool isgreeted(int a, int b){
    if((arr[a] - a >= 0 && arr[b] - b >= 0) || (arr[a] - a <= 0 && arr[b] - b <= 0)) {//same direct
        if(( a > b && arr[a] < arr[b] )|| (a < b && arr[a] > arr[b])){
            return true;
        }
    }else{
        if((arr[a] < arr[b] && arr[a] < b )|| (arr[b] < a && b < a)){
            return false;
        }else{
            return true;
        }
    }
    return false;



}



signed main(){
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    
    int n = input();

    rep(i,0,n) arr.push_back(input()-1);

    int ans = 0;

    rep(i,0,n){
        rep(j, i + 1, n){
            if(isgreeted(i,j)) ans++;
        }
    }

    print(ans);



}