#include <bits/stdc++.h>
using namespace std;
#pragma warning(disable : 4996);
long long int n, h[1000007], d[1000007][2], mod = 1e9 + 7;
void solve() {
  long long int i, j;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> h[i];
    h[i] -= 1;
  }
  h[n] = 0;
  d[0][0] = max((long long int)0, h[0] - h[1]);
  d[0][1] = min(h[0], h[1]);
  for (i = 1; i < n; i++) {
    long long int k = min(h[i - 1], h[i]);
    d[i][0] = d[i - 1][1] * max((long long int)0, k - h[i + 1]);
    d[i][0] %= mod;
    d[i][0] = (d[i][0] + max((long long int)0, h[i] - h[i + 1])) % mod;
    d[i][1] = d[i - 1][1] * min(h[i + 1], k);
    d[i][1] %= mod;
    d[i][1] = (d[i][1] + min(h[i], h[i + 1])) % mod;
  }
  long long int ans = 0;
  for (i = 0; i < n; i++) {
    ans = (ans + d[i][0] + d[i][1]) % mod;
  }
  cout << ans;
}
int main() {
#pragma comment(linker, "/STACK:1073741824"
  solve();
  return 0;
}
