uses crt;
var tbc:real;
n,i,d1,d2,tong1,tong2:longint;
begin
clrscr;
write('Nhap n=');readln(n);
d1:=0; d2:=0; tong1:=0; tong2:=0;
for i:=1 to n do
begin
if i mod 2=0 then
begin
d1:=d1+1;
tong1:=tong1+i;
end;
if i mod 2<>0 then
begin
d2:=d2+1;
tong2:=tong2+i;
end;
end;
tbc:=(tong1+tong2)/n;
writeln('a=',tbc:0:2);
writeln('b');
writeln('chan=',d1);
writeln('le=',d2);
readln;
end.