Cod sursa(job #1568435)
Utilizator | Data | 14 ianuarie 2016 11:24:25 | |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.4 kb |
#include <fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int v[1000005];
int main()
{
int n,s=0;
fin>>n;
for(int i=1; i<=n; i++)
v[i]=i;
for(int i=2; i<=n; i++)
if(v[i]==i)
for(int j=i; j<=n; j=j+i)
v[j]-=v[j]/i;
for(int i=1; i<=n; i++)
s=s+v[i];
s=s*2-1;
fout<<s;
}