#include <bits/stdc++.h> using namespace std; #define int long long void solve(){ int n, t; cin >> n >> t; vector<int> a(n + 1); for(int i = 1; i <= n; i++){ cin >> a[i]; a[i] %= t; } sort(a.begin() + 1, a.end()); int ans = (a[n] - a[1] + 1) / 2; for(int i = 2; i <= n; i++) ans = min(ans, (t + a[i - 1] - a[i] + 1) / 2); cout << ans; } signed main(){ ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); solve(); }