#include <iostream>
#include <fstream>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cassert>
#include <tuple>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <unordered_set>
#include <unordered_map>
#include <numeric>
using namespace std;
typedef long long LL;
typedef vector<int> Vi;
typedef vector<LL> VL;
typedef vector<bool> Vb;
typedef vector<vector<int>> Vii;
#define forR(i, n) for (int i = 0; i < (n); i++)
Vi ask(int i);
int cntV = 0, N, cntNotV;
int ask_cache[200003][2];
Vi askC(int i) {
if (ask_cache[i][0] >= 0) {
return Vi{ ask_cache[i][0], ask_cache[i][1] };
}
Vi rs = ask(i);
ask_cache[i][0] = rs[0]; ask_cache[i][1] = rs[1];
return rs;
}
int getLeftNonVCnt(int i) {
int c = 0;
while (true) {
if (i >= N) return cntNotV - c;
Vi rs = askC(i);
if (rs[0] + rs[1] == cntNotV) {
// is a IV node
return rs[0] - c;
} else {
i++;
c++;
}
}
}
int find_best_(int n) {
N = n;
memset(ask_cache, -1, sizeof(ask_cache));
if (n <= 5000) {
forR(i, n) {
Vi rs = askC(i);
if (rs[0] == 0 && rs[1] == 0)
return i;
}
}
cntV = INT_MAX;
forR(i, 500) {
Vi rs = askC(i);
if (rs[0] == 0 && rs[1] == 0) return i;
cntV = min(cntV, n - rs[0] - rs[1]);
}
cntNotV = n - cntV;
auto getTth = [n](int t) {
// goal: get the t-th non-V node
int l = 0, r = n - 1;
while (l < r) {
int mid = (l + r) / 2;
if (getLeftNonVCnt(mid + 1) >= t) {
r = mid;
} else {
l = mid + 1;
}
}
return l;
};
int cntIV = INT_MAX; // cnt_ge_IV
for (int t = 1; t <= 30; t++) {
int node = getTth(t);
// l is the t-th non-V node
assert(getLeftNonVCnt(node) == t - 1);
Vi rs = askC(node);
assert(rs[0] + rs[1] < cntNotV);
if (rs[0] == 0 && rs[1] == 0) return node;
cntIV = min(cntIV, n - rs[0] - rs[1]);
}
int cntLtIV = n - cntIV;
auto getLeftNonVICnt = [&getTth, cntLtIV](int i_cntV) {
int c = 0;
while (true) {
if (i_cntV > cntNotV) return cntLtIV - c;
Vi rs = askC(getTth(i_cntV));
assert(rs[0] + rs[1] <= cntLtIV);
if (rs[0] + rs[1] == cntLtIV) {
// is a IIV node
return rs[0] - c;
} else {
i_cntV++;
c++;
}
}
};
for (int t = 1; t <= cntLtIV; t++) {
// goal: get the t-th non-IV node
int l = 1, r = cntNotV;
while (l < r) {
int mid = (l + r) / 2;
if (getLeftNonVICnt(mid + 1) >= t) {
r = mid;
} else {
l = mid + 1;
}
}
// l is the t-th non-IV node
int node = getTth(l);
Vi rs = askC(node);
assert(rs[0] + rs[1] < cntLtIV);
if (rs[0] == 0 && rs[1] == 0) return node;
}
return -1;
//int l = 0, r = n - 1;
//while (l < r) {
// int mid = (l + r) / 2;
// Vi rs = ask(mid);
// if (rs[0] == rs[1]) return mid;
// if (rs[0] == 1) {
// r = mid - 1;
// } else {
// l = mid + 1;
// }
//}
//return l;
}
int find_best(int n) {
int result = find_best_(n);
forR(i, 5000) ask(i);
return result;
}
#ifdef TEST_LOCAL
Vi _answer{ 2,2,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,2 };
Vi ask(int i) {
int n = _answer.size();
assert(i >= 0 && i < n);
int l = 0, r = 0;
for (int j = 0; j < n; j++) {
if (_answer[j] < _answer[i]) {
if (j < i) l++; else r++;
}
}
return Vi{ l, r };
}
int main() {
_answer = Vi(6000, 4);
_answer[3] = 3;
forR(i, 100) {
_answer[1000 + i * 10] = 3;
}
_answer[5997] = 2;
_answer[5998] = 2;
_answer[5999] = 1;
auto r = find_best(_answer.size());
return 0;
}
#endif
