this is my general code:
Procedure Solve;
  var L,R,M : LongInt;
 BeGiN
  L:=0;
  R:=10000001;
  While R - L > 1 do
   Begin
    M:=(L + R) shr 1;
    if Can(M) then L:=M
              else R:=M;
   End;
  While (Can(L + 1)) and (L < 10000000) do Inc(L);
  Answer:=L;
 EnD;
Who see mistake???
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Sorry my English is Bad:)

[code deleted]

Edited by moderator 05.12.2023 19:55

My reason for WA # 24 was a bug in code of reading data
You need to change a(i,j) AND a(j,i). I didn't do that and had WA.

What's more, here are some tests if anebody needs:
4 5
1 4 1000 3001000
1 2 440 3001200
1 3 449 3001500
3 2 1 3001500
2 4 990 3001500

answer 15

4 5
1 4 1000 3001000
1 2 440 3001200
1 3 450 3001500
3 2 1 3001500
2 4 990 3001500

answer 12