Cod sursa(job #1800816)
Utilizator | Andrei Cotor Andrei_Cotor | Data | 8 noiembrie 2016 09:44:15 |
---|---|---|---|
Problema | Fractii | Scor | 90 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.41 kb |
#include<fstream>
using namespace std;
ifstream fi("fractii.in");
ofstream fo("fractii.out");
long long n,i,A[1000001],j,rez;
int main()
{
fi>>n;
for(i=1; i<=n; i++)
A[i]=i-1;
for(i=2; i<=n; i++)
{
for(j=2*i; j<=n; j+=i)
{
A[j]-=A[i];
}
rez+=A[i];
}
fo<<2*rez+1<<"\n";
fi.close();
fo.close();
return 0;
}