#include "bits/stdc++.h"

#define REP(i,num) for(int i=0;i<(num);++i)
#define ALL(c) c.begin(),c.end()
#define LOOP(i) while(i--)
#define PRINTALL(c) for(auto pitr=c.begin();pitr!=c.end();++pitr){cout<<*pitr;if(next(pitr,1)!=c.end())cout<<' ';}cout<<endl;
#define PAIRCOMP(c,comp) [](const pair<ll,ll>& lhs,const pair<ll,ll>& rhs){return lhs.c comp rhs.c;}

using namespace std;
using ll = long long;

constexpr ll atcoder_mod = 1e9+7;

template<typename T=int>
T in(){T x; cin >> x; return (x);}
template<typename T=int,typename C=vector<T>>
C vecin(int N){C x(N);REP(i,N){x[i]=in<T>();}return move(x);}

void vout(){cout << endl;}
template<typename Head,typename... Tail>
void vout(Head&& h,Tail&&... t){cout << ' ' << h;vout(forward<Tail>(t)...);}
void out(){cout << endl;}
template<typename Head,typename... Tail>
void out(Head&& h,Tail&&... t){cout << h;vout(forward<Tail>(t)...);}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);

	int N=in();
	out(180*(N-2));
	return 0;
}

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using vi = vector<ll>;
using vii = vector<vi>;
using Pll = pair<ll, ll>;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define all(v) v.begin(), v.end()
#define sz(x) ((int) x.size())
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define F first
#define S second
const int MOD = 1e9+7;
const int INF = 2e9;
template<class T> void print(const T& t){ cout << t << endl; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
int gcd(int a,int b){return b?gcd(b,a%b):a;}

int main(){
    ll n;
    cin >> n;
    print(180 * (n - 2));
}