#include <bits/stdc++.h>

using namespace std;
#define all(a)a.begin(),a.end()
using ll=long long;
const int INF = 1<<30;
const ll INFll =1LL<<62;
const int mod =(1e9)+7;
using P = pair<ll,ll>;

int main() {
    int n;cin >>n;
    n-=2;
    cout <<n*180<<endl;
    return 0;
}


#include <bits/stdc++.h>  // ver1.8
#define int long long
#define ALL(v) (v).begin(),(v).end()
#define Vi vector<int>
#define pb push_back
#define mp make_pair
#define rep(i,a,b) for(int i=a;i<b;i++)
#define repeq(i,a,b) for(int i=a;i<=b;i++)
#define repr(i,a,b) for(int i=a;i>b;i--)
#define repreq(i,a,b) for(int i=a;i>=b;i--)
#define leng(n) (int)(log10(n)+1)
#define INF 9000000000000000000  //  9.0 * 10^18
#define MOD 1000000007  //  10^9 + 7
#define PAI 3.14159265358979
using namespace std;

int gcd(int a,int b){return b?gcd(b,a%b):a;}  //  最大公約数gcd
int lcm(int a,int b){return a/gcd(a,b)*b;}  //  最小公倍数lcm

signed main() {
  cout << fixed << setprecision(14);
  int n,k;
  cin>>n>>k;
  cout << 180*(n-2)<< endl;
  return 0;
}
