Cod sursa(job #670002)
| Utilizator |  mitru carmen carmenus |
Data | 28 ianuarie 2012 09:54:55 |
|---|---|---|---|
| Problema | Fractii | Scor | 100 |
| Compilator | cpp | Status | done |
| Runda | Arhiva de probleme | Marime | 0.31 kb |
#include <cstdio>
int v[1000005];
int main()
{
int n,i,j;
long long rez=0;
freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);
scanf("%d",&n);
for(i=2;i<=n ; ++i )
v[i]=i-1;
for( i=2 ; i<n ; i++ )
{
for( j=i+i; j<=n; j+=i )
v[j]-=v[i];
rez+=v[i];
}
rez+=v[i];
printf("%lld",2*rez+1);
}