Problem:
Score : 100 points

Problem Statement

Given an integer N not less than 3, find the sum of the interior angles of a regular polygon with N sides.

Print the answer in degrees, but do not print units.

Constraints

3 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print an integer representing the sum of the interior angles of a regular polygon with N sides.

Sample Input 1

3

Sample Output 1

180

The sum of the interior angles of a regular triangle is 180 degrees.

Sample Input 2

100

Sample Output 2

17640

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>

using namespace std;
using ll = long long;
using ld = long double;

#define ALL(x) begin(x), end(x)
#define REP(i, n) for (size_t i = 0, i##_len = (n); i < i##_len; ++i)

void solve(ll N) {
  cout << (N-2)*180 << endl;
}

int main() {
  ll N;
  cin >> N;
  solve(N);
  return 0;
}