#include <bits/stdc++.h>
#include "coins.h"
#define pb push_back
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vll vector<ll>
#define all(v) v.begin(), v.end()
#define whole(a) a+1, a+1+n
#define OPT ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define sec second
#define fi first
#define print(k) cerr << "Ans : "; cout << k << endl;
#define ins insert
#define pb push_back
#define bpc __builtin_popcountll
#define skip continue
#define endll '\n'
#define gcd(a, b) __gcd(a, b)
#define lcm(a, b) a*b / (__gcd(a, b))
#define mpr make_pair
#define rep(i,l,r) for(ll i=l;i<=r;++i)
#define new '\n'
typedef long long ll;
typedef unsigned long long ull;
const int mod = 998244353;
const int sz = 3e5+5;
using namespace std;
int dx[4] = {1,0,-1,0};
int dy[4] = {0,1,0,-1};
vector <int> coin_flips(vector<int> b,int c)
{
int x = 0;
for(int i = 0; i < 64; ++i)
{
if(b[i])
{
x ^= i;
}
}
x ^= c;
vector<int>flips(1);
flips[0] = x;
return flips;
}
int find_coin(vector<int> b)
{
int x = 0;
for(int i = 0; i < 64; ++i)
{
if(b[i])
{
x ^= i;
}
}
return x;
}
