#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 100 + 10;
const int inf = 1000000000;
int dp[MAX_N][3];
int main() {
  int n, a, b, c;
  cin >> n >> a >> b >> c;
  for (int i = 0; i < MAX_N; i++) {
    for (int j = 0; j < 3; j++) {
      dp[i][j] = inf;
    }
  }
  dp[1][0] = 0;
  for (int i = 2; i <= n; i++) {
    dp[i][0] = min(dp[i - 1][1] + b, dp[i - 1][2] + a);
    dp[i][1] = min(dp[i - 1][0] + b, dp[i - 1][2] + c);
    dp[i][2] = min(dp[i - 1][1] + c, dp[i - 1][0] + a);
  }
  cout << min(min(dp[n][0], dp[n][1]), dp[n][2]) << endl;
}
