uses crt;
var e,t,s:real;
n:integer;
begin
clrscr;
e:=0.0001;
s:=0;
t:=-1;
n:=0;
while abs(t)>e do
begin
n:=n+1;
t:=-t/(n*n);
s:=s+t;
end;
write('S=',s:0:5);
readln
end.
uses crt;
var e,t,s:real;
n:integer;
begin
clrscr;
e:=0.0001;
s:=0;
t:=-1;
n:=0;
while abs(t)>e do
begin
n:=n+1;
t:=-t/(n*n);
s:=s+t;
end;
write('S=',s:0:5);
readln
end.