#ifdef LOCAL #define _GLIBCXX_DEBUG #endif #include using namespace std; #define rep(i,s,t) for(ll i = (ll)(s); i < (ll)(t); i++) #define rrep(i,s,t) for(ll i = (ll)(s-1);(ll)(t) <= i; i--) #define all(x) (x).begin(), (x).end() typedef long long ll; typedef long double ld; typedef pair Pll; typedef vector vl; typedef vector vvl; typedef vector vvvl; constexpr ll INF = numeric_limits::max()/4; constexpr ll n_max = 2e5+10; #define int ll const long double pi = 3.14159265358979323846; const long double eps = 1e-12; template string to_string(pair p); string to_string(const string &s) {return '"' + s + '"';} string to_string(const char *c) {return to_string((string) c);} string to_string(bool b) {return (b ? "true" : "false");} template string to_string(bitset v){ string res = ""; for(size_t i = 0; i < N; i++) res += static_cast('0' + v[i]); return res; } template string to_string(A v) { bool first = true; string res = "{"; for(const auto &x : v) { if(!first) res += ", "; first = false; res += to_string(x); } res += "}"; return res; } template string to_string(pair p){return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";} void debug_out() {cerr << endl;} template void debug_out(Head H, Tail... T) { cerr << " " << to_string(H); debug_out(T...); } #ifdef LOCAL #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__) #else #define debug(...) 42 #endif template bool chmax(T &a, T b){if(a < b){a = b; return true;} return false;} template bool chmin(T &a, T b){if(a > b){a = b; return true;} return false;} signed main(){ cin.tie(nullptr); ios::sync_with_stdio(false); ll n; cin >> n; vector a(n); for(int i = 0; i < n; i++) cin >> a[i]; sort(all(a)); bool ok = false; rep(i,0,n-1){ if (a[i] + 1 == a[i + 1]) ok = true; } cout << (ok ? 2 : 1) << endl; }