Cod sursa(job #1812969)
Utilizator | Data | 22 noiembrie 2016 16:34:50 | |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.46 kb |
#include <iostream>
#include <cstdio>
using namespace std;
int n,p=0;
int a[2000001];
int main()
{
freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);
scanf("%d",&n);
for(int i=1;i<=n;i++)
{
a[i]=i-1;
}
for(int i=2;i<=n;i++)
{
for(int j=i+i;j<=n;j+=i)
a[j]-=a[i];
}
for(int i=1;i<=n;i++)
{
p+=2*a[i];
}
printf("%d",p+1);
return 0;
}