Cod sursa(job #271154)
Utilizator | Data | 4 martie 2009 22:27:27 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.39 kb |
#include <stdio.h>
char v[2000100];
int i,n,j,count;
int main ()
{
freopen ("ciur.in","r",stdin);
freopen ("ciur.out","w",stdout);
scanf ("%d",&n);
for (i=2;i*i<=n;i++)
if (v[i]==0) for (j=i*i;j<=n;j=j+i) v[j]=1;
for (i=2;i<=n;i++) count=count+v[i];
printf ("%d",n-1-count);
return 0;
}