Cod sursa(job #166452)
Utilizator | Data | 28 martie 2008 00:28:17 | |
---|---|---|---|
Problema | Fractii | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.71 kb |
#include<stdio.h>
#define M 1000002
long sol[M],n,suma,i,j;
int main()
{
freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);
scanf("%ld",&n);
suma=1;
for(i=2;i<=n;i++)
if (!sol[i])
{
suma+=2*(i-1);
for(j=i+i;j<=n;j+=i)
if (sol[j])
sol[j]=(sol[j]*(i-1))/i;
else
sol[j]=(j*(i-1))/i;
}
else
suma+=2*sol[i];
printf("%ld",suma);
return 0;
}