Cod sursa(job #642037)
Utilizator | Data | 30 noiembrie 2011 14:50:01 | |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.35 kb |
#include<fstream>
using namespace std;
int main(){
long long numar=0;
int n,i,j,v[10000003];
ifstream fin("fractii.in");
ofstream fout("fractii.out");
fin>>n;
for(i=2;i<=n;i++)
v[i]=i-1;
for(i=2;i<=n;i++){
numar=numar+v[i];
for(j=2*i;j<=n;j+=i)
v[j]-=v[i];
}
numar=numar*2+1;
fout<<numar;
return 0;
}.