#include <iostream> #include <cstdlib> #include <vector> #include <algorithm> using namespace std; int main() { int n; cin >> n; vector<int> as(n); for (int& a : as) { cin >> a; } sort(as.begin(), as.end()); bool len = false; for (int i = 0; i < n - 1; i++) { if (as[i] + 1 == as[i + 1]) { len = true; } } cout << (len ? 2 : 1) << endl; }