1/
uses crt;
var i,n,s: integer;
begin
clrscr;
write ('nhap n: '); readln (n);
for i:=1 to n do if i mod 2<>0 then s:=s+1;
writeln ('tong la: ',s);
readln;
end.
2/
uses crt;
var i,n,s,ss: integer;
begin
clrscr;
write ('nhap s: '); readln (s);
repeat
i:=i+1;
ss:=ss+i;
if ss=s then n:=i;
until ss=s;
writeln ('gia tri cua n la: ',n);
readln;
end.