Cod sursa(job #714181)
| Utilizator |  Astalas Paul paul777 |
Data | 15 martie 2012 15:12:14 |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 100 |
| Compilator | fpc | Status | done |
| Runda | Arhiva educationala | Marime | 0.33 kb |
var a:array[1..2000000000]of boolean;f,g:text;n,i,j,x:longint;
begin
assign(f,'ciur.in');reset(f);
assign(g,'ciur.out');rewrite(g);
read(f,n);
for i:=1 to n do a[i]:=true;
for i:=2 to n do
if a[i]=true then for j:=2 to n div i do a[i*j]:=false;
x:=0;
for i:=2 to n do
if a[i]=true then x:=x+1;
write(g,x);close(f);close(g);end.