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

using ll = long long;

int main() {
   ios::sync_with_stdio(false);
   cin.tie(nullptr);
   int n;
   cin >> n;
   vector<int> a(n);
   for (auto &it : a) {
      cin >> it;
   }
   int cnt = 1;
   int curr = a[0];
   ll sum = 0;
   for (int i = 1; i < n; i++) {
      if (abs(a[i] - curr) == 1) cnt++;
      else {
         // every subarray is valid add it to the sum
         sum += 1LL * cnt * (cnt - 1) / 2;
         cnt = 1;
      }
      curr = a[i];
   }
   sum += 1LL * cnt * (cnt - 1) / 2;

   cout << sum << "\n";
   
}