#include<bits/stdc++.h>
#define ios ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define dec(x, y) fixed << setprecision((y)) << (x)
#define xx first
#define yy second
#define srt(v) sort((v).begin(), (v).end())
#define srtr(v) sort((v).rbegin(), (v).rend())
#define pb push_back
#define popb pop_back
#define sz(a) (int)(a).size()
#define len(a) (int)(a).length()
#define mp make_pair
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
vector<int> coin_flips(vector<int> b, int c) {
int vr=0;
for(int i=0; i<64; ++i) {
vr^=b[i];
}
vr^=c;
vector<int> d(1);
d[0]=vr;
return d;
}
int find_coin(vector<int> b) {
int vr=0;
for(int i=0; i<64; ++i) {
vr^=b[i];
}
return vr;
}
