{N+}
uses crt;
var n,i,j:byte;
s,p:extended;
begin
clrscr;
write('n=');
readln(n);
s:=0;
for i:=1 to n do
begin
p:=1;
for j:=i to 2*i do
p:=p*j;
s:=s+p;
end;
write('S=',s:0:0);
readln
end.
{N+}
uses crt;
var n,i,j:byte;
s,p:extended;
begin
clrscr;
write('n=');
readln(n);
s:=0;
for i:=1 to n do
begin
p:=1;
for j:=i to 2*i do
p:=p*j;
s:=s+p;
end;
write('S=',s:0:0);
readln
end.