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  1. #include <bits/stdc++.h>
  2. #define int long long
  3. using namespace std;
  4. const int MOD = 998244853;
  5.  
  6. signed main() {
  7. ios_base::sync_with_stdio(0);
  8. cin.tie(0);
  9. int n, a, b, c;
  10. cin >> n >> a >> b >> c;
  11. int dp[n + 1];
  12. dp[0] = 1;
  13. for (int i = 1; i <= n; ++i) {
  14. dp[i] = (dp[i - 1] * a) % MOD;
  15. if (i > 1) dp[i] = (dp[i] + dp[i - 2] * b) % MOD;
  16. if (i > 2) dp[i] = (dp[i] + dp[i - 3] * b) % MOD;
  17. }
  18. cout << dp[n];
  19. return 0;
  20. }
Success #stdin #stdout 0s 5320KB
stdin
3 2 1 1
stdout
13