Cod sursa(job #306626)

Utilizator ConsstantinTabacu Raul Consstantin Data 21 aprilie 2009 17:59:00
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.32 kb
Raporteaza aceasta sursa 
#include<stdio.h>

unsigned long long int v[1000001],i,j,k,l,m,n,sol;

int main(){

freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);

scanf("%lld",&n);

for(i=1;i<=n;i++)
	v[i]=i-1;

for(i=2;i<=n;i++)
	{for(j=2*i;j<=n;j+=i)
		v[j]-=v[i];
	sol+=2*v[i];}
	
printf("%lld",sol+1);

return 0;}