Cod sursa(job #36520)
Utilizator | Cretu Iulian c_iulyan | Data | 23 martie 2007 17:54:11 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.4 kb |
#include<fstream.h>
ifstream f("fractii.in");
ofstream g("fractii.out");
int a[1000];
long long n,k;
void erat(long long x)
{k=0;
for(long long i=2;i<x;i++)
if(a[i]==0&&x%i==0)
for(long long j=i;j<x;j=j+i)
{a[j]=1; k++;}
}
int main()
{
f>>n;
long long t=0;
for(long long i=3;i<=n;i++)
{memset(a,0,sizeof(a));
erat(i);
t=t+i-k-2;
}
g<<2*(t+n)-1;
return 0;
}