Cod sursa(job #661630)

Utilizator raazvvannheghedus razvan raazvvann Data 14 ianuarie 2012 20:03:28
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.35 kb
Raporteaza aceasta sursa 
//		http://infoarena.ro/problema/fractii
#include <fstream>
#define DIM 1000001
using namespace std;

ifstream f("fractii.in");
ofstream g("fractii.out");

int v[DIM];

int main()
{
	long long i,j,n,nr=0;
	f>>n;
	for(i=2;i<=n;i++) v[i]=i-1;
	for(i=2;i<=n;i++) 
	{
		for(j=i+i;j<=n;j+=i)
			v[j]-=v[i];
		nr+=v[i];
	}
	
	g<<2*nr+1;
}