COROANA
#include<iostream>
using namespace std;
int binarySearch(int arr[], int l, int r, int x) {
while (l <= r) {
int m = l + (r - l) / 2;
if (arr[m] == x)
return m;
if (arr[m] < x)
l = m + 1;
else
r = m - 1;
}
return -1;
}
int main() {
int a[10001], b[10001], n;
cin >> n;
for (int i = 1; i <= n; i++)
cin >> a[i];
for (int i = 1; i <= n - 1; i++)
cin >> b[i];
for (int i = 1; i <= n; i++)
if (binarySearch(b, 1, n - 1, a[i]) == -1) {
cout << a[i] << ' ';
return 0;
}
return 0;
}