const maxn=;

      maxm=;

var eg:array[..maxm,..] of longint;

    f:array[..maxn*] of longint;

    i,j,m,n,x,y,z:longint;

procedure swap(var a,b:longint);

var c:longint;

begin

    c:=a;a:=b;b:=c;

end;

function find(x:longint):longint;

begin

    if f[x]=x then exit(x);

    f[x]:=find(f[x]);

    exit(f[x]);

end;

procedure sort(l,r:longint);

var i,j,x:longint;

begin

    i:=l; j:=r;

    x:=eg[(l+r) div ,];

    while i<=j do

    begin

        while eg[i,]>x do inc(i);

        while x>eg[j,] do dec(j);

        if i<=j then

        begin

            swap(eg[i,],eg[j,]);

            swap(eg[i,],eg[j,]);

            swap(eg[i,],eg[j,]);

            inc(i);

            dec(j);

        end;

    end;

    if i<r then sort(i,r);

    if l<j then sort(l,j);

end;

begin

    readln(n,m);

    for i:= to m do read(eg[i,],eg[i,],eg[i,]);

    for i:= to n* do f[i]:=i;

    sort(,m);

    for i:= to m do

    begin

        x:=find(eg[i,]);

        y:=find(eg[i,]);

        if x=y then

        begin

            writeln(eg[i,]);

            exit;

        end;

        f[x]:=find(eg[i,]+n);

        f[y]:=find(eg[i,]+n);

    end;

    writeln();

end.