Cod sursa(job #191573)

Utilizator raduzerRadu Zernoveanu raduzer Data 27 mai 2008 13:34:32
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.32 kb
Raporteaza aceasta sursa 
#include <stdio.h>

long long n,i,j,a[1000002];
int main()
{
	freopen("fractii.in","r",stdin);
	freopen("fractii.out","w",stdout);
	scanf("%lld",&n);
	for (i=1; i<=n; ++i) a[i]=i-1;
	for (i=2; i<=n; ++i)
		for (j=i*2; j<=n; j+=i) a[j]-=a[i];
	for (i=0, j=0; i<=n; ++i, j+=a[i]);
	printf("%lld",j*2+1);
	return 0;
}