#include <bits/stdc++.h>
using namespace std;
ifstream fin ("sumtri.in");
ofstream fout ("sumtri.out");
int a[105][105], c[105][105], d[105][105],n,t[105][105];
int main()
{
int i,j;
fin>>n;
for(i=1;i<=n;i++)
for(j=1;j<=i;j++)
fin>>t[i][j];
for(j=1;j<=n;j++)
c[n][j]=t[n][j];
for(i=n-1;i>=1;i--)
for(j=1;j<=i;j++)
if(c[i+1][j]>c[i+1][j+1])
{
c[i][j]=t[i][j]+c[i+1][j];
d[i][j]=j;
}
else
{
c[i][j]=t[i][j]+c[i+1][j+1];
d[i][j]=j+1;
}
fout<<c[1][1]<<endl;
return 0;
}
{"html5":"htmlmixed","css":"css","javascript":"javascript","php":"php","python":"python","ruby":"ruby","lua":"text\/x-lua","bash":"text\/x-sh","go":"go","c":"text\/x-csrc","cpp":"text\/x-c++src","diff":"diff","latex":"stex","sql":"sql","xml":"xml","apl":"apl","asterisk":"asterisk","c_loadrunner":"text\/x-csrc","c_mac":"text\/x-csrc","coffeescript":"text\/x-coffeescript","csharp":"text\/x-csharp","d":"d","ecmascript":"javascript","erlang":"erlang","groovy":"text\/x-groovy","haskell":"text\/x-haskell","haxe":"text\/x-haxe","html4strict":"htmlmixed","java":"text\/x-java","java5":"text\/x-java","jquery":"javascript","mirc":"mirc","mysql":"sql","ocaml":"text\/x-ocaml","pascal":"text\/x-pascal","perl":"perl","perl6":"perl","plsql":"sql","properties":"text\/x-properties","q":"text\/x-q","scala":"scala","scheme":"text\/x-scheme","tcl":"text\/x-tcl","vb":"text\/x-vb","verilog":"text\/x-verilog","yaml":"text\/x-yaml","z80":"text\/x-z80"}