Cod sursa(job #1729890)
Utilizator | Gigel Fronel Gigel-Frone | Data | 15 iulie 2016 19:12:23 |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.39 kb |
#include <cstdio>
using namespace std;
int main()
{
freopen("fractii.in", "r", stdin);
freopen("fractii.out", "w", stdout);
int n, v[1000005];
scanf("%d", &n);
long long x=0;
for(int i=1; i<=n; i++) v[i]=i-1;
for(int i=2; i<=n; i++)
{
x=x+v[i];
for(int j=2*i; j<=n; j=j+i) v[j]=v[j]-v[i];
}
printf("%lld", 2*x+1);
}