Cod sursa(job #202876)
Utilizator | Florin C FlorinC1996 | Data | 11 august 2008 21:41:08 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.63 kb |
#include <stdio.h>
#define NMAX(1 << 20)
int N;
long long rez;
int v[NMAX];
int main()
{
freopen("fractii.in", "r", stdin);
freopen("fractii.out", "w", stdout);
int i, j;
scanf("%d", &N);
for(i = 2; i <= N; i++)
{
v[i] = i-1-v[i];
for(j = 2; j*i <= N; j++)
v[i*j] += v[i];
}
for(i = 2; i <= N; i++)
rez += (long long)v[i]*2;
rez++;
printf("%lld\n", rez);
return 0;
}