/*************************************
* author: marvinthang *
* created: 08.03.2023 17:37:48 *
*************************************/
#include <bits/stdc++.h>
#include "towns.h"
using namespace std;
#define fi first
#define se second
#define left ___left
#define right ___right
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define MASK(i) (1LL << (i))
#define BIT(x, i) ((x) >> (i) & 1)
#define __builtin_popcount __builtin_popcountll
#define ALL(v) (v).begin(), (v).end()
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define REPD(i, n) for (int i = (n); i--; )
#define FOR(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define FORD(i, b, a) for (int i = (b), _a = (a); --i >= _a; )
#define FORE(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORDE(i, b, a) for (int i = (b), _a = (a); i >= _a; --i)
#define scan_op(...) istream & operator >> (istream &in, __VA_ARGS__ &u)
#define print_op(...) ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
#include "debug.h"
#else
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define DB(...) 23
#define db(...) 23
#define debug(...) 23
#endif
template <class T> scan_op(vector <T>) { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> scan_op(pair <U, V>) { return in >> u.fi >> u.se; }
template <class U, class V> print_op(pair <U, V>) { return out << '(' << u.first << ", " << u.second << ')'; }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")"; else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class A, class B> bool minimize(A &a, B b) { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b) { if (a < b) { a = b; return true; } return false; }
// end of template
int hubDistance(int N, int sub) {
int u = 0, v = 0, diameter = 0;
vector <int> dist(N);
REP(love, 2) {
pair <int, int> f;
REP(i, N) if (i != u) {
dist[i] = getDistance(u, i);
maximize(f, make_pair(dist[i], i));
}
v = u; u = f.se; diameter = f.fi;
}
int res = diameter;
REP(w, N) if (w != u && w != v) {
int v_to_city = (diameter + dist[w] - getDistance(u, w)) / 2;
minimize(res, max(v_to_city, diameter - v_to_city));
}
return res;
}
#ifdef LOCAL
#include "graderlib.c"
int main() {
FILE *f;
f = freopen("towns.in","r",stdin);
assert(f != NULL);
f = freopen("towns.out","w",stdout);
assert(f != NULL);
int ncase, R, N;
int subtask;
int ret;
ret = scanf("%d%d",&subtask,&ncase);
assert(ret == 2);
for (int i = 0; i < ncase; i++) {
ret = scanf("%d",&N);
assert(ret == 1);
_ini_query(N,subtask);
R=hubDistance(N,subtask);
printf("%d\n",R);
}
return 0;
}
#endif
