Cod sursa(job #632873)

Utilizator OpportunityVlad Negura Opportunity Data 12 noiembrie 2011 14:50:56
Problema Fractii Scor 0
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.3 kb
Raporteaza aceasta sursa 
#include<fstream.h>
long long a[10001],i,j,n,s=1;
ifstream fin("fractii.in");
ofstream fout("fractii.out");

void main(){

  fin>>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=1; i<=n; i++)
   s+=a[i]*2;

  fout<<s;
}