Cod sursa(job #420869)
| Utilizator |  Asofronie Samuel samuel91 |
Data | 20 martie 2010 18:12:44 |
|---|---|---|---|
| Problema | Fractii | Scor | 100 |
| Compilator | cpp | Status | done |
| Runda | Arhiva de probleme | Marime | 0.32 kb |
#include <fstream>
using namespace std;
long long n,x[1000005],i,j,S=0;
int main()
{
ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
for(i=2;i<=n;i++)
x[i]=i-1;
for(i=2;i<=n;i++)
{
S=S+x[i];
for(j=i*2;j<=n;j=j+i)
x[j]=x[j]-x[i];
}
S=S*2+1;
g<<S;
f.close();
g.close();
return 0;
}