Cod sursa(job #386722)
Utilizator | Echo Slam Selony | Data | 25 ianuarie 2010 19:53:52 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | c | Status | done |
Runda | Arhiva de probleme | Marime | 0.57 kb |
#include <stdio.h>
#define nrmax 1000001
#define _fin "fractii.in"
#define _fout "fractii.out"
long long n,i,A[nrmax];
int main()
{
freopen(_fin,"r",stdin);
freopen(_fout,"w",stdout);
scanf("%lld",&n);
for (i=1;i<=n;i++)
A[i]=i-1;
for (i=2;i<=n;i++ )
{
long long k=2;
while (k*i<=n)
{
A[k*i]-=A[i];
k++;
}
}
long long sum=0;
for (i=1;i<=n;i++)
sum+=A[i];
sum*=2; sum++;
printf("%lld\n",sum);
fout<<endl;
fclose(stdin);
fclose(stdout);
return 0;
}