Cod sursa(job #2268110)
Utilizator | Data | 24 octombrie 2018 15:01:54 | |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.58 kb |
#include <cstdio>
using namespace std;
int v[1000000];
int ciur (int n)
{
int i;
for(i=2;i<=n;i++)
{
v[i]=i;
}
for (i=2;i<=n;i++)
{
if (v[i]==i)
{
for (int j=i;j<=n;j+=i)
{
v[j]=v[j]/i*(i-1);
}
}
}
}
int main()
{
freopen("fractii.in","r",stdin);
freopen ("fractii.out","w",stdout);
int n,i;
long long s=1;
scanf("%d",&n);
ciur(n);
for (i=1;i<=n;i++)
{
s=s+2*v[i];
}
printf("%d",s);
return 0;
}