CONST Dim = 31;
      INF = 1000000000;

VAR D:Array[0..Dim,0..Dim,0..Dim] of longint;
    P:Array[1..Dim] of integer;
    R:Array[0..Dim,0..Dim] of longint;
    NL:integer;

PROCEDURE ReadData;
var K,i,j:integer;
begin
  for i:=0 to Dim do
    for j:=0 to Dim do
      for k:=0 to Dim do D[i,j,k]:=INF;

  readln(NL);
  for i:=1 to NL do
  begin
    readln(P[i]);
    for j:=1 to P[i] do
    begin
      repeat
        read(K);
        if K=0 then break;
        read(D[i-1,K,j]);
      until false;
      readln;
    end;
    readln;
  end;
end;

PROCEDURE Solve;
var Best,L,k,i,j,dd:longint;
begin
  for i:=0 to Dim do
    for j:=0 to Dim do R[i,j]:=INF;
  for i:=1 to P[1] do R[1,i]:=D[0,1,i];
  for L:=1 to NL-1 do
    for j:=1 to P[L] do
      if R[L,j]<>INF then
        for k:=1 to P[L+1] do
        begin
          dd:=R[L,j]+D[L,j,k];
          if dd<R[L+1,k] then R[L+1,k]:=dd;
        end;
  Best:=INF;
  for i:=1 to P[NL] do
    if R[NL,i]<Best then Best:=R[NL,i];
  writeln(Best);
end;

BEGIN
  ReadData;
  Solve;
END.