#include #include using namespace std; using namespace atcoder; using mint = modint1000000007; int main() { ios::sync_with_stdio(false); cin.tie(0); int N; cin >> N; vector A(N); for (int i = 0; i < N; i++) { cin >> A[i]; } vector B; for (int i = 0; i < N; i++) { if (A[i] != 0) { B.push_back(A[i]); } } mint ans = 0; for (int i = 0; i < (int)(B.size()); i++) { if (i == 0) { ans += B[i]; } else if (i == 1) { if (A[i] == 1) { ans += B[i]; } else { ans *= B[i]; } } else { ans *= B[i]; } } cout << ans.val() << endl; return 0; }