Cod sursa(job #1284692)
Utilizator | Tudor Coman tudorcoman | Data | 6 decembrie 2014 19:10:24 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.45 kb |
#include <cstdio>
#define ll long long
#define VL 1000005
using namespace std;
ll k;
int n,i,j;
int v[VL];
void val()
{
scanf("%d",&n);
for(i=2;i<=n;++i)
v[i]=i-1;
}
int main()
{
freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);
val();
for(i=2;i<=n;++i)
{
for(j=++i;j<=n;j+=i)
v[j]-=v[i];
k+=v[i];
}
k=k*2+1;
printf("%d\n",k);
return 0;
}