import java.io.*; import java.util.*; public class Main { static InputStream is; static PrintWriter out; static String INPUT = ""; static void solve() { int n = ni(); ArrayList a = new ArrayList<>(); for(int i = 0; i < n; i++){ a.add(ni()); } System.out.println(f(a,30)); } private static int f(ArrayList a , int pos){ if(pos < 0) return 0; ArrayList zero = new ArrayList<>(); ArrayList one = new ArrayList<>(); for(int i = 0; i < a.size(); i ++){ if(((a.get(i)>>pos)&1) == 0){ zero.add(a.get(i)); } else one.add(a.get(i)); } if(one.size() == 0){ return f(zero, pos-1); } else if(zero.size() == 0) { return f(one, pos - 1); } else{ return 1<= lenbuf){ ptrbuf = 0; try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); } if(lenbuf <= 0)return -1; } return inbuf[ptrbuf++]; } private static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); } // private static boolean isSpaceChar(int c) { return !(c >= 32 && c <= 126); } private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; } private static double nd() { return Double.parseDouble(ns()); } private static char nc() { return (char)skip(); } private static String ns() { int b = skip(); StringBuilder sb = new StringBuilder(); while(!(isSpaceChar(b))){ sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } private static char[] ns(int n) { char[] buf = new char[n]; int b = skip(), p = 0; while(p < n && !(isSpaceChar(b))){ buf[p++] = (char)b; b = readByte(); } return n == p ? buf : Arrays.copyOf(buf, p); } private static char[][] nm(int n, int m) { char[][] map = new char[n][]; for(int i = 0;i < n;i++)map[i] = ns(m); return map; } private static int[] na(int n) { int[] a = new int[n]; for(int i = 0;i < n;i++)a[i] = ni(); return a; } private static int ni() { int num = 0, b; boolean minus = false; while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')); if(b == '-'){ minus = true; b = readByte(); } while(true){ if(b >= '0' && b <= '9'){ num = num * 10 + (b - '0'); }else{ return minus ? -num : num; } b = readByte(); } } private static long nl() { long num = 0; int b; boolean minus = false; while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')); if(b == '-'){ minus = true; b = readByte(); } while(true){ if(b >= '0' && b <= '9'){ num = num * 10 + (b - '0'); }else{ return minus ? -num : num; } b = readByte(); } } private static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); } private static int[] nsi(){ char[] s = ns().toCharArray(); int[] a = new int[s.length]; for(int j = 0; j < s.length; j++){ a[j] = s[j] - '0'; } return a; } }