Cod sursa(job #291115)
Utilizator | Data | 29 martie 2009 13:39:21 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | fpc | Status | done |
Runda | The Beginners | Marime | 0.5 kb |
program Ciur;
var n,i,j,k,l:longint;
a:array[1..20000000] of byte;
f:text;
begin
assign(f,'ciur.in');
reset(f);
readln(f,n);
close(f);
for i:=1 to n do
a[i]:=1;
a[1]:=0;
k:=0;
for i:=2 to n do
if (a[i]=1) then
begin
j:=2*i;
inc(k);
while j<=n do
begin
a[j]:=0;
inc(j,i);
end;
end;
assign(f,'ciur.out');
rewrite(f);
writeln(f,k);
close(f);
end.