Cod sursa(job #223532)

Utilizator ye_kai008Ye Kai ye_kai008 Data 28 noiembrie 2008 19:08:52
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.35 kb
Raporteaza aceasta sursa 
#include<stdio.h>
int main()
{
	int e[1000001], i, j, n;
	freopen("fractii.in","r",stdin);
	freopen("fractii.out", "w", stdout);
	scanf("%d", &n);
	for(i=2;i<=n;i++)
		e[i]=i;
	for(i=2;i<=n;i++)
		if(e[i]==i)
			for(j=i;j<=n;j+=i)
				e[j]=e[j]/i*(i-1);
	long long s=0;
	for(i=2;i<=n;i++)
		s=s+e[i];
	printf("%lld", 1+2*s);
	return 0;
}