var
a:array[1..70,1..70]of real;
i,j,n,kol:integer;
sum:real;
begin
writeln('vvedite razmer mafricy N');
readln(n);
writeln('vvedite elementy matricy');
for i:=1 to n do
for j:=1 to n do
read(a[i,j]);
writeln('matrica');
for i:=1 to n do
begin
for j:=1 to n do
write(a[i,j]:5:1);
writeln;
end;
for i:=1 to n do
for j:=1 to n do
if (i>j)and(a[i,j]<0)then
begin
sum:=sum+a[i,j];
inc(kol);
end;
if kol>0 then writeln('srednee=',sum/kol:5:1)
else writeln('otricatelnyh net');
end.