输入边数与矩阵
program agrinet;
var
  n,i,j,minj:integer;
  mark:array[1..100] of boolean;
  map:array[1..100,1..100] of longint;
  dist:array[1..100] of longint;
  min,ans:longint;
begin
  ans:=0;
  readln(n);
  for i:=1 to n do
    for j:=1 to n do
      read(map[i,j]);
  for i:=1 to n do dist[i]:=maxlongint;
  dist[1]:=0;
  mark[1]:=true;
  minj:=1;
  for i:=1 to n-1 do begin
    for j:=1 to n do
      if dist[j]>map[minj,j] then begin dist[j]:=map[minj,j];  end;
    min:=maxlongint;
    for j:=1 to n do
      if (dist[j]<min) and (not mark[j]) then begin
        minj:=j;
        min:=dist[j];
      end;
    mark[minj]:=true;
    inc(ans,min);
  end;
writeln(ans);
end.