Cod sursa(job #2498968)
Utilizator | Banilean Alexandru-Ioan alex_bb8 | Data | 24 noiembrie 2019 22:40:01 |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.39 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
int n;
int64_t v[1000003],sol;
int main()
{
f>>n;
for(int i=1;i<=n;i++) v[i]=i;
for(int i=2;i<=n;i++)
{
if(v[i]==i)
{
for(int j=i;j<=n;j+=i)
{v[j]/=i;v[j]*=(i-1);}
}
sol+=v[i];
}
g<<2*sol+1;
return 0;
}