Cod sursa(job #637985)
Utilizator | Data | 20 noiembrie 2011 17:57:01 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.32 kb |
#include<fstream>
using namespace std;
int i,j,n,nr[10000001];
long long max1=0;
int main()
{
ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
for(i=2;i<=n;i++)
nr[i]=i-1;
for(i=2;i<=n;i++)
{
max1+=nr[i];
for(j=i+i;j<=n;j+=i)
nr[j]-=nr[i];
}
max1=max1*2+1;
g<<max1;
return 0;
}