#include "souvenirs.h"
#include <utility>
#include <vector>
#include <bits/stdc++.h>
using ll = long long;
using namespace std;
void buy_souvenirs(int N, long long P0) {
int n = N;
vector<ll> p(N, -1);
p[0] = P0;
ll p0 = P0;
vector<int> amount_needed(N);
for(int i = 0; i < n; i++) amount_needed[i] = i;
pair<vector<int>, ll> buy = transaction(p0 - 2);
int a = buy.first[0];
ll change = buy.second;
int b = -1;
if(buy.first.size() == 2) b = buy.first[1];
// if we brought a singular 1
if(a == 1 && b == -1){
p[a] = P0 - 2 - change;
transaction(p[a] - 1);
transaction(p[a] - 1);
return;
}
// if we only brought 2
if(a == 2 && b == -1){
p[2] = P0 - 2 - change;
p[1] = p0 - 1;
transaction(p[1]);
transaction(p[2]);
return;
}
// if we brought a and b
// t = p0 + a + b
ll s = p0 - 2 - change;
// p0 > a > s / 2
// 0 < b < s / 2
// for(auto e : p) cout << e << " ";
transaction(s / 2);
}
