Cod sursa(job #1471642)
Utilizator | Mereu Alexandra Alexandraaaa | Data | 14 august 2015 19:10:17 |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.43 kb |
#include <iostream>
#include <fstream>
using namespace std;
int v[1000005];
int main(){
ifstream f("fractii.in");
ofstream g("fractii.out");
int n, i,j;
f >> n;
long long s = 0;
for (i = 2; i <= n; ++i) {
v[i] = i - 1;
}
for (i = 2; i <= n; ++i) {
for (j = 2 * i; j <= n; j += i){
v[j] -= v[i];
}
s =(1LL * v[i] * 2) + s;
}
s++;
g << s;
f.close();
g.close();
return 0;
}