#define _USE_MATH_DEFINES
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <clocale>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <queue>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

#define IOS ios::sync_with_stdio(false); cin.tie(0);
#define FOR(i, s, n) for(int i = (s), i##_len=(n); i < i##_len; ++i)
#define FORS(i, s, n) for(int i = (s), i##_len=(n); i <= i##_len; ++i)
#define VFOR(i, s, n) for(int i = (s); i < (n); ++i)
#define VFORS(i, s, n) for(int i = (s); i <= (n); ++i)
#define REP(i, n) FOR(i, 0, n)
#define REPS(i, n) FORS(i, 0, n)
#define VREP(i, n) VFOR(i, 0, n)
#define VREPS(i, n) VFORS(i, 0, n)
#define RFOR(i, s, n) for(int i = (s), i##_len=(n); i >= i##_len; --i)
#define RFORS(i, s, n) for(int i = (s), i##_len=(n); i > i##_len; --i)
#define RREP(i, n) RFOR(i, n, 0)
#define RREPS(i, n) RFORS(i, n, 0)
#define ALL(v) (v).begin(), (v).end()
#define SORT(v) sort(ALL(v))
#define RSORT(v) sort(ALL(v), greater<decltype(v[0])>())
#define SZ(x) ((int)(x).size())
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define MT make_tuple
#define BIT(n) (1LL<<(n))
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())

using ll = long long;
using ui = unsigned int;
using ull = unsigned long long;
using Pi_i = pair<int, int>;
using VB = vector<bool>;
using VC = vector<char>;
using VD = vector<double>;
using VI = vector<int>;
using VLL = vector<ll>;
using VS = vector<string>;
using VSH = vector<short>;
using VULL = vector<ull>;

const int MOD = 1000000007;
const int INF = 1000000000;
const int NIL = -1;
const double EPS = 1E-10;

template<class T, class S>
bool chmax(T &a, const S &b){
    if(a < b){
        a = b; return true;
    }
    return false;
}
template<class T, class S>
bool chmin(T &a, const S &b){
    if(b < a){
        a = b; return true;
    }
    return false;
}




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

#include <algorithm>
#include <climits>
#include <iostream>
#include <string>
#include <utility>
#include<vector>
#include<iomanip>
#include<map>
#include <queue>
#include<cmath>
#include<cstdio>
#include<iomanip>
#include<set>
#include <bits/stdc++.h>
 
using namespace std;
using ll = long long int;
 
#define REP(i,n) for(ll i=0;i<(ll)(n);i++) //REP(i, 5) cout<<i;
#define REPD(i,n) for(ll i=(ll)(n)-1;i>=0;i--)
#define FOR(i,a,b) for(ll i=(a);i<=(b);i++)
#define MOD 1000000007 //10^9+7
//#define MOD 1
 
ll gcd(ll a, ll b) {
  ll tmp;
  if ( b > a) {
    tmp = a;
    a = b;
    b = tmp;
  }
  while (a % b !=0) {
    tmp = b;
    b = a % b;
    a = tmp;
  }
  return b;
}
 
const int MAX = 1000;
 
ll table[MAX][MAX];
 
// テーブルを作る前処理
void COMinit() {
    table[0][0] = table[0][1] = 1;
    FOR(i, 1, MAX-1){
      FOR(j, 0, i+1){
        if(j==0) table[i][j] = 1;
        else if(j == i+1) table[i][j] = 1;
        else table[i][j] = table[i-1][j-1]+table[i-1][j];
      }
    }
}
 
// 二項係数計算
ll COM(ll n, ll k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return table[n-1][k];
}

void sosuu(ll n, vector<ll> &v){

  vector<ll> num(n, 0);

  FOR(i, 1, sqrt(n)){
    if(num[i]==0){
      FOR(j, 0, n/i){
        num[i+(j*i)] = 1;
      }
    }
  }
  REP(i, n){
    if(num[i]==0) v.push_back(i+1);
  }
}


int main(void){
 
   double n;
   cin>>n;

    cout<<(n-2)*180.0<<endl;
  return 0;
}