Cod sursa(job #2742555)
Utilizator | Data | 21 aprilie 2021 10:11:49 | |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.52 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int f[1000005];
void ciur(int n)
{
int i,j;
f[1]=f[2]=1;
for(i=1; i<=n; i++)
f[i]=i;
for(i=2; i<=n; i++)
{
for(j=2*i; j<=n; j+=i)
f[j]-=f[i];
}
}
int main()
{
int n;
fin>>n;
ciur(n);
long long ans=0;
for(int i=1; i<=n; i++)
{
ans+=f[i];
}
ans*=2;
ans++;
fout<<ans<<"\n";
return 0;
}