#include <bits/stdc++.h>
using namespace std;
#include "gap.h"
/*
static void my_assert(int k){ if (!k) exit(1); }
static int subtask_num, N;
static long long A[100001];
static long long call_count;
void MinMax(long long s, long long t, long long *mn, long long *mx)
{
int lo = 1, hi = N, left = N+1, right = 0;
my_assert(s <= t && mn != NULL && mx != NULL);
while (lo <= hi){
int mid = (lo+hi)>>1;
if (A[mid] >= s) hi = mid - 1, left = mid;
else lo = mid + 1;
}
lo = 1, hi = N;
while (lo <= hi){
int mid = (lo+hi)>>1;
if (A[mid] <= t) lo = mid + 1, right = mid;
else hi = mid - 1;
}
if (left > right) *mn = *mx = -1;
else{
*mn = A[left];
*mx = A[right];
}
if (subtask_num == 1) call_count++;
else if (subtask_num == 2) call_count += right-left+2;
}
*/
typedef long long ll;
ll f(ll l, ll r, ll pl, ll pr, ll zz){
//cout << l << " " << r << " " << zz << " cc\n";
if(l > r || zz <= 0) return pr-pl;
ll mn,mx;
MinMax(l,r,&mn,&mx);
//cout << l << " " << r << " " << << " " << pr << " ss\n";
//cout << mn << " " << mx << " aa\n";
ll t = max(mn-pl , pr-mx);
return max(t , f(mn+1,mx-1,mn,mx,zz-2));
}
long long findGap(int T, int n){
if(T == 1) return f(0,1e18,1e18,0,n);
ll las=0, t=1, res=1, mn, mx;
for(;;){
MinMax(las+1,las+t,&mn,&mx);
if(mn == -1) { t += t; continue; }
else { res = max(res , las ? mn-las : 0); las = mx; t = res; }
MinMax(las+1,1e18,&mn,&mx);
if(mn == -1) return res;
}
return 0;
}
/*
int main()
{
//FILE *in = stdin, *out = stdout;
//my_assert(2 == fscanf(in, "%d%d", &subtask_num, &N));
//my_assert(1 <= subtask_num && subtask_num <= 2);
//my_assert(2 <= N && N <= 100000);
//for (int i=1;i<=N;i++) my_assert(1 == fscanf(in, "%lld", A+i));
//for (int i=1;i<N;i++) my_assert(A[i] < A[i+1]);
A[1] = 2;
A[2] = 3;
A[3] = 6;
A[4] = 8;
N = 4;
subtask_num = 2;
printf("%lld\n", findGap(2, 4));
printf("%lld\n", call_count);
}
*/
