Cod sursa(job #708862)
| Utilizator |  Avram Bogdan Bigb21 |
Data | 7 martie 2012 13:07:16 |
|---|---|---|---|
| Problema | Fractii | Scor | 0 |
| Compilator | cpp | Status | done |
| Runda | Arhiva de probleme | Marime | 0.35 kb |
#include<fstream>
using namespace std;
ifstream in("fractii.in");
ofstream out("fractii.out");
long v[1000000];
int main ()
{
int i,n,s=0,j;
in>>n;
for(i=3;i<=n;i++)
{if(v[i]==0)
for(j=i*i;j<=n;j=j+i)
v[j]=1;
}
for(i=1;i<=n;i++)
if(v[i]==0)
s++;
out<<n*s-n+1;
}