#include "coins.h"
#include <bits/stdc++.h>
#define range(it, a, b) for (ll it = a; it < b; it++)
#define invr(it, a, b) for (ll it = a; it >= b; it--)
#define all(x) begin(x), end(x)
#define ll long long
#define ull unsigned long long
#define ld long double
#define INF64 ((ll) 1 << 62)
#define INF32 (1 << 30)
#define mset multiset
#define uset unordered_set
#define umap unordered_map
#define pqueue priority_queue
#define ptr(A) shared_ptr<A>
#define v(x) vector<x>
using namespace std;
v(int) coin_flips (v(int) b, int c) {
v(int) ans;
int a = c;
range(i, 0, 64) {
if (b[i])
a ^= i;
}
ans.push_back(a);
return ans;
}
int find_coin(v(int) b) {
int a = 0;
range(i, 0, 64) {
if (b[i])
a ^= i;
}
return a;
}
