/in/foo.cc: In function 'int main()':
/in/foo.cc:17:28: error: 'M' was not declared in this scope
   dp[i] = ((i - 3) * q - f+M) % M;
                            ^
/in/foo.cc:7:11: warning: unused variable 'ans' [-Wunused-variable]
  ll n, i, ans = 1, c1, c2, j;
           ^~~
/in/foo.cc:7:20: warning: unused variable 'c1' [-Wunused-variable]
  ll n, i, ans = 1, c1, c2, j;
                    ^~
/in/foo.cc:7:24: warning: unused variable 'c2' [-Wunused-variable]
  ll n, i, ans = 1, c1, c2, j;
                        ^~
/in/foo.cc:7:28: warning: unused variable 'j' [-Wunused-variable]
  ll n, i, ans = 1, c1, c2, j;
                            ^