#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;
}
#include <bits/stdc++.h>
#define sz(arr) (int)arr.size()
#define all(arr) arr.begin(), arr.end()

using namespace std;

void _cin() {}
template <class Head, class... Tail>
void _cin(Head&& head, Tail&&... tail) {
  cin >> head;
  _cin(forward<Tail>(tail)...);
}

#define Cin(T, ...) \
  T __VA_ARGS__;    \
  _cin(__VA_ARGS__)

int main() {
  Cin(int, n);
  cout << 180 * (n - 2) << endl;

  return 0;
}