#include<bits/stdc++.h> using namespace std; int main() { int n; cin >> n; int sum_total = (n - 2) * 180; int sum_known = 0; int x; for(int i = 1; i <= n - 1; i++) { cin >> x; sum_known += x; } int ans = sum_total - sum_known; cout << ans; return 0; }