#include <bits/stdc++.h>
using namespace std;
int main()
{
int n, x;
cin >> n >> x;
int sum = 0;
for(int i = 0; i < n - 1; i += 1){
int a_i;
cin >> a_i;
sum += a_i;
}
int ans = x - sum;
if(ans <= 0)
cout << "Another mistake!" << endl;
else
cout << ans << endl;
return 0;
}
