Cod sursa(job #2837383)
Utilizator | Data | 22 ianuarie 2022 10:18:14 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.52 kb |
#include <iostream>
#include <fstream>
using namespace std;
int n;
long long sum;
long long a[1000005];
ifstream fin("fractii.in");
ofstream fout("fractii.out");
void initial()
{
a[1] = 1;
for(int i = 2; i <= n; i++)
a[i] = i - 1;
}
void scadere()
{
for(int i = 2; i <= n; i++)
{
sum += a[i];
for(int j = i + i; j <= n; j += i)
a[j] -= a[i];
}
sum *= 2;
fout << sum + 1;
}
int main()
{
fin >> n;
initial();
scadere();
}