Cod sursa(job #1620943)
Utilizator | aaa aaa gorni97 | Data | 29 februarie 2016 14:26:53 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.52 kb |
#include <iostream>
#include <fstream>
#define maxn 1000000
using namespace std;
int main()
{long long s;
int n,i,j;
long long phi[maxn];
fstream f("fractii.in",ios::in);
fstream g("fractii.out",ios::out);
f>>n;
for(i=1;i<=n;i++)
phi[i]=i;
for(i=2;i<=n;i++)
if(phi[i]==i)
for(j=1;j<=n;j=j+i)
phi[j]=(phi[j]*(i-1))/i;
s=1;
for(i=2;i<=n;i++)
s=s+phi[i]*2;
g<<s;
g.close();
f.close();
}