Cod sursa(job #623214)
Utilizator | Data | 19 octombrie 2011 15:20:11 | |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.44 kb |
#include <fstream>
using namespace std;
ifstream in("fractii.in");
ofsteam out("fractii.out");
const int N = 1000000;
int e[N];
int main()
{
int i,n,j;
in>>n;
for (i = 1;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);
for(i=1;i<=n;i++)
s+=e[i];
out<<s<<'\n';
return 0;
}