const N=1000;
var K: array [1..N] of integer;
i,A,B,C: integer;
W: real;
begin
for i:=1 to N do K[i]:=random(101)-50;
A:=0;
B:=0;
C:=1;
for i:=1 to N do begin
if K[i]>0 then A:=A+K[i];
if K[i]<0 then B:=B+1;
if i mod 2<>0 then C:=C*K[i];
end;
W:=B+(A-B)/(C+1);
writeln(W);
end.
const N=1000;
var K: array [1..N] of integer;
i,A,B,C: integer;
W: real;
begin
for i:=1 to N do K[i]:=random(101)-50;
A:=0;
B:=0;
C:=1;
for i:=1 to N do begin
if K[i]>0 then A:=A+K[i];
if K[i]<0 then B:=B+1;
if i mod 2<>0 then C:=C*K[i];
end;
W:=B+(A-B)/(C+1);
writeln(W);
end.