#include <iostream>
#include <cmath>
using namespace std;
const int MAX = 1e7 + 1;
int main()
{
	int n, a, maxx;
	long long ans = 0;
	cin >> n;
	cin >> maxx;
	for(int i = 2; i <= n; i++)
	{
		cin >> a;
		ans += min(maxx, a);
		maxx = max(maxx, a);
	}
	cout << ans << endl; 
}