#include <bits/stdc++.h>
using namespace std;
long long n, m;
long long a[10001], f[10001];
int main() {
  int d, x, y;
  scanf("%I64d %I64d", &n, &m);
  f[0] = f[1] = 1;
  for (int i = 2; i <= n; i++) f[i] = f[i - 1] + f[i - 2], f[i] %= 1000000000LL;
  for (int i = 1; i <= n; i++) scanf("%I64d", &a[i]);
  for (int i = 1; i <= m; i++) {
    scanf("%I64d", &d);
    if (d == 1) {
      scanf("%I64d %I64d", &x, &y);
      a[x] = y;
    } else {
      long long ans = 0;
      scanf("%I64d %I64d", &x, &y);
      for (int i = x; i <= y; i++) ans += f[i - x] * a[i], ans %= 1000000000LL;
      printf("%I64d\n", ans);
    }
  }
  return 0;
}
