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

建三个变量a,b,c思路：a-2*180,180-b,c