program Pr115_3; var k, n : integer; suma : real; begin readln(n); suma := 0; for k := 1 to n do suma := suma + 1 / sqr(2*k+1); writeln(suma); readln; end.
program Pr115_3;var
k, n : integer;
suma : real;
begin
readln(n);
suma :=0;for k :=1tondo
suma := suma +1/sqr(2*k+1);writeln(suma);
readln;
end.