Cod sursa(job #305092)
Utilizator | balint andrei andrei_balint | Data | 16 aprilie 2009 11:01:36 |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.37 kb |
#include<fstream>
using namespace std;
ifstream cin("fractii.in");
ofstream cout("fractii.out");
int v[1000000],n;
void oiler()
{
int i,j;
for(i=2;i<=n;i++)
v[i]=i;
for(i=2;i<=n;i++)
if(v[i]==i)
for(j=i;j<=n;j=j+i)
v[j]=v[j]/i*(i-1);
}
int main()
{
int s=0,i;
cin>>n;
oiler();
for(i=2;i<=n;i++)
s=v[i]+s;
s=s*2+1;
cout<<s;
return 0;
}