include[HTML_REMOVED]
using namespace std;
const int N = 510;
long long a[N][N];
int n;
int charge(int x)
{
if(x == 1) return a[1][1];
else
{
x –;
for(int i = 1;i <= x;i ++)
{
if(a[x+1][i] > a[x+1][i+1]) a[x][i] += a[x+1][i];
else a[x][i] += a[x+1][i+1];
}
charge(x);
}
}
int main()
{
cin >> n;
for(int i = 1;i <= n;i )
{
for(int j = 1;j <= i;j )
{
cin >> a[i][j];
}
}
int res = charge(n);
cout << res;
return 0;
}