const n=10;
var a: array [1..n] of integer;
    i, j, k: integer;
begin
     randomize;
     for i:=1 to n do
     begin
     a[i]:=random(100);
     write (a[i], ' ');
     end;
     k:=0;
     for i:=1 to n-4 do
        for j:=i+4 to n do
           if ((a[i]*a[j]) mod 10=1) then k:=k+1;
     writeln;
     write('k=',k);
end.