#include "gap.h"
#include <bits/stdc++.h>
// #include <ext/rope>
// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;
// using namespace __gnu_cxx;
using namespace std;
// #define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define ll long long
#define ull unsigned long long
#define ld long double
#define pb push_back
#define bit(mask, i) ((mask >> i) & 1)
#define el '\n'
#define F first
#define S second
template <class X, class Y> bool maximize(X &x, const Y &y) { return (x < y ? x = y, 1 : 0); }
template <class X, class Y> bool minimize(X &x, const Y &y) { return (x > y ? x = y, 1 : 0); }
const int INF = 1e9;
const ll LINF = 1e18;
const int MOD = 1e9 + 7;
const int MULTI = 0;
const ld eps = 1e-9;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0}; // R D L U
const int ddx[4] = {-1, 1, 1, -1}, ddy[4] = {1, 1, -1, -1}; // UR DR DL UL
const char cx[4] = {'R', 'D', 'L', 'U'};
const ll base = 31;
const int nMOD = 2;
const ll mods[] = {(ll)1e9 + 10777, (ll)1e9 + 19777, (ll)1e9 + 3, (ll)1e9 + 3777};
const int maxn = 1e5 + 5;
int n, a[maxn];
ll solve1() {
ll limL = 0, limR = LINF, mn, mx;
int i = 1, j = n;
while (i <= j) {
MinMax(limL, limR, &mn, &mx);
a[i] = mn; a[j] = mx;
limL = a[i] + 1;
limR = a[j] - 1;
i++; j--;
}
ll res = 0;
for (int i = 1; i < n; ++i)
maximize(res, a[i + 1] - a[i]);
return res;
}
ll solve2() {
return -1;
}
ll findGap(int T, int N) {
n = N;
return (T == 1 ? solve1() : solve2());
}
// signed main() {
// ios_base::sync_with_stdio(0);
// cin.tie(0); cout.tie(0);
// #ifndef ONLINE_JUDGE
// freopen("input.inp", "r", stdin);
// freopen("output.out", "w", stdout);
// #endif
// if (!MULTI) solve();
// else {
// int test; cin >> test;
// while (test--) solve();
// }
// return 0;
// }
