Cod sursa(job #443750)
Utilizator | Data | 18 aprilie 2010 11:58:29 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.33 kb |
#include<stdio.h>
long long nr=0;
int i,j,n,v[1000001];
int main()
{
freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);
scanf("%d",&n);
for(i=2;i<=n;i++)
v[i]=i-1;
for(i=2;i<=n;i++)
{
nr=nr+v[i];
for(j=i+i;j<=n;j=j+i)
v[j]=v[j]-v[i];
}
nr=nr*2+1;
printf("%lld",nr);
return 0;
}