Cod sursa(job #2779860)
Utilizator | Data | 5 octombrie 2021 11:44:59 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.54 kb |
#include <fstream>
using namespace std;
ifstream in("fractii.in");
ofstream out("fractii.out");
const int NMAX=1e6+5;
long long v[NMAX];
int main()
{
int n,i,j;
in>>n;
for(i=2;i<=NMAX;i++)
{
v[i]=i;
}
for(i=2;i<=NMAX;i++)
{
if(v[i]==i)
{
for(j=i;j<=NMAX;j=j+i)
{
v[j]=v[j]/i*(i-1);
}
}
}
long long suma=0;
for(i=1;i<=n;i++)
{
suma=suma+v[i];
}
out<<suma*2+1;
return 0;
}