#include "gap.h"
#include<bits/stdc++.h>
using namespace std;
long long ans = 0;
long long dfs(long long l, long long r)
{
if (r - l <= ans)
return ans;
if (r - l <= 1)
return ans = max(ans, r - l);
if (r - l == 2)
{
long long tl, tr;
MinMax(l, l + 1, &tl, &tr);
if (tr == l + 1)
return ans = max(ans, 1LL);
else
return ans = max(ans, 2LL);
}
if (r - l == 3)
{
long long tl, tr;
MinMax(l + 1, r - 1, &tl, &tr);
if (tl == l + 1 && tr == r - 1)
return ans = max(ans, 1LL);
else if (tl == l + 1 || tr == r - 1)
return ans = max(ans, 2LL);
else
return ans = max(ans, 3LL);
}
long long m = (l + r) / 2, ll, lr, rl, rr;
MinMax(l + 1, m, &ll, &lr), MinMax(m + 1, r - 1, &rl, &rr);
long long ret = ans;
if (ll == -1 && rr == -1)
ret = r - l;
else if (ll == -1)
{
ret = max({ret, rl - l, r - rr});
if (rr - rl > ret)
ret = max(ret, dfs(rl, rr));
}
else if (rr == -1)
{
ret = max({ret, ll - l, r - lr});
if (lr - ll > ret)
ret = max(ret, dfs(ll, lr));
}
else
{
ret = max({ret, ll - l, rl - lr, r - rr});
if (lr - ll > ret)
ret = max(ret, dfs(ll, lr));
if (rr - rl > ret)
ret = max(ret, dfs(rl, rr));
}
return ans = max(ans, ret);
}
long long findGap(int T, int N)
{
long long l, r;
MinMax(0, 1000000000000000000, &l, &r);
return dfs(l, r);
}
