var a:array[1..3,1..3] of integer; t:array[0..2] of boolean; k:array[0..2] of integer; i,j:integer; res:boolean;begin for i := 1 to 3 do for j := 1 to 3 do read(a[i,j]); for i := 0 to 2 do begin k[i] := 0; t[i] := false; end; for i := 1 to 3 do for j := 1 to 3 do k[a[i,j]] := k[a[i,j]] + 1; for i := 1 to 3 do begin if (a[i,1] = a[i,2]) and (a[i,2] = a[i,3]) then t[a[i,1]] := true; if (a[1,i] = a[2,i]) and (a[2,i] = a[3,i]) then t[a[1,i]] := true; end; if (a[1,1] = a[2,2]) and (a[2,2] = a[3,3]) then t[a[2,2]] := true; if (a[3,1] = a[2,2]) and (a[2,2] = a[1,3]) then t[a[2,2]] := true; res := true; if (k[1] - k[2] > 1) or (k[1] - k[2] < 0) then res := false; if t[1] and ( t[2] or (k[1] = k[2]) ) then res := false; if res then writeln('YES') else writeln('NO')end.