143-2=141
141/2=70.5=70
270
270+2=272
2722
2722.5
2722.52
Procedure SumKol(var n,k,s:integer);
begin
if n>0 then begin
s:=s+n mod 10;
k:=k+1;
n:=n div 10;
SumKol(n,k,s)
end
end;
function Mean(n:integer):real;
var k,s:integer;
begin
k:=0; s:=0;
SumKol(n,k,s);
if k>0 then Mean:=s/k else Mean:=0
end;
var
n,k,s:integer;
m:real;
begin
Read(n);
Writeln(Mean(n))
end.
Var i,k:integer;
s:real;
begin
k:=2;
for i:=1 to 25 do
begin
s:=s+sqrt(k);
k:=k+2
end;
WriteLn(s)
end.