//#include #include #include #include #include #include #include #include // string, to_string, stoi #include // vector #include // min, max, swap, sort, reverse, lower_bound, upper_bound #include // pair, make_pair #include // tuple, make_tuple #include // int64_t, int*_t #include // printf #include // map #include // queue, priority_queue #include // set #include // stack #include // deque #include // unordered_map #include // unordered_set #include // bitset #include // isupper, islower, isdigit, toupper, tolower using namespace std; //using namespace atcoder; using ll = long long; #define all(A) A.begin(),A.end() #define rep(i, n) for (long long i = 0; i < (long long)(n); i++) ll Max(ll(a), ll(b), ll(c)) { return max(max(a, b), c); } ll Min(ll(a), ll(b), ll(c)) { return min(min(a, b), c); } void aN(bool ch) { if (ch)cout << "Yes" << endl; else cout << "No" << endl; return; } int main() { ll N; cin >> N; vector A(N); rep(i, N) { cin >> A[i]; } sort(all(A)); bool ch = true; rep(i, N - 1) { if (A[i] + 1 == A[i + 1]) { ch = false; } } if (ch)cout << 1 << endl; else cout << 2 << endl; }