#include "bits/stdc++.h"
#include "gap.h"
using namespace std;
#define ff first
#define ss second
#define all(v) v.begin(), v.end()
#define ll long long
#define pb push_back
#define pii pair<int, int>
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
const int MOD = 1e9+7;
const int N = 1e5+5;
ll a[N];
ll findGap(int t, int n){
if(t == 1){
ll l = 0, r = 1e18, id = 0, mn, mx, ans = 0;
for(int i = 0; i < (n+1)/2; ++i){
MinMax(l, r, &mn, &mx);
a[id++] = mn, a[id++] = mx, l = mn+1, r = mx-1;
}
sort(a, a+n);
for(int i = 0; i < n-1; ++i)
umax(ans, a[i+1]-a[i]);
return ans;
}
ll s, T;
MinMax(0, LLONG_MAX, &s, &T); //n + 1
ll d = (T-s+n)/(n-1), mx = 0, a = s;
while(s + 1 < T){
ll x, y;
MinMax(s+1, min(s+d, T-1), &x, &y);
if(~x){
umax(mx, x-a);
a = y;
}
s += d;
}
umax(mx, T-a);
return mx;
}
