#include "prize.h"
#include <bits/stdc++.h>
#define Loop(x,l,r) for (ll x = (l); x < (ll)(r); ++x)
#define LoopR(x,l,r) for (ll x = (r)-1; x >= (ll)(l); --x)
typedef long long ll;
typedef std::pair<int, int> pii;
typedef std::pair<ll , ll > pll;
using namespace std;
static const int N = 200'010;
static int cnt[N];
static int *dard = new int[8];
static int test(int *a, int n)
{
fill(cnt, cnt+n, 0);
int pos = -1;
int mx = 1;
Loop (i,0,n) {
if (a[i] > n || 1 > a[i])
return -1;
if (a[i] > mx)
mx = a[i];
if (a[i] == 1)
pos = i;
cnt[a[i]-1]++;
}
if (cnt[0] != 1)
return -1;
Loop (i,0,mx-1)
if ((ll)cnt[i] * cnt[i] >= cnt[i+1])
return -1;
return pos;
}
int find_best(int n)
{
int rem = n, mx = 0, cnt_nxt = 1;
while (rem >= cnt_nxt) {
rem -= cnt_nxt;
++mx;
cnt_nxt = cnt_nxt*cnt_nxt + 1;
}
int *r = dard;
int *l = dard;
cerr << "dard = " << dard << '\n';
for (;;) {
if (*r < 1 || mx < *r)
l = r+1;
++r;
if (r - l == n) {
int tmp = test(l, n);
if (tmp != -1)
return tmp;
++l;
}
}
return -1;
}
