Cod sursa(job #330743)
Utilizator | Data | 11 iulie 2009 14:01:33 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.35 kb |
#include<fstream>
#define dmax 1000002
using namespace std;
ifstream in("fractii.in");
ofstream out("fractii.out");
int nr[dmax],n;
long long k;
int main()
{ int i,j;
in>>n;
in.close();
for(i=1;i<=n;i++)
nr[i]=i-1;
for(i=2;i<=n;i++)
{ for(j=2*i;j<=n;j+=i)
nr[j]-=nr[i];
k+=2*nr[i];
}
k++;
out<<k;
out.close();
return 0;
}