#include <bits/stdc++.h>
using namespace std;
template <class T>
void splitstr(const string &s, vector<T> &out) {
  istringstream in(s);
  out.clear();
  copy(istream_iterator<T>(in), istream_iterator<T>(), back_inserter(out));
}
template <class T>
T gcd(T a, T b) {
  return b ? gcd(b, a % b) : a;
}
static void redirect(int argc, const char **argv) {
  if (argc > 1) {
    static filebuf f;
    f.open(argv[1], ios::in);
    cin.rdbuf(&f);
    if (!cin) {
      cerr << "Failed to open '" << argv[1] << "'" << endl;
      exit(1);
    }
  }
  if (argc > 2) {
    static filebuf f;
    f.open(argv[2], ios::out | ios::trunc);
    cout.rdbuf(&f);
    if (!cout) {
      cerr << "Failed to open '" << argv[2] << "'" << endl;
    }
  }
}
int main(int argc, const char **argv) {
  redirect(argc, argv);
  int N, M;
  cin >> N >> M;
  vector<long long> a(N);
  for (int i = 0; i < N; i++) cin >> a[i];
  vector<long long> fib(N + 1);
  fib[0] = fib[1] = 1;
  for (int i = 2; i <= N; i++) fib[i] = (fib[i - 2] + fib[i - 1]) % 1000000000;
  for (int i = 0; i < M; i++) {
    int t;
    cin >> t;
    switch (t) {
      case 1: {
        int x, v;
        cin >> x >> v;
        x--;
        a[x] = v;
      } break;
      case 2: {
        int l, r;
        cin >> l >> r;
        l--;
        long long ans = 0;
        for (int i = l; i < r; i++)
          ans = (ans + fib[i - l] * a[i]) % 1000000000;
        cout << ans << '\n';
      } break;
    }
  }
  return 0;
}
