Cod sursa(job #968364)
Utilizator | Casu-Pop Andrei andy1496 | Data | 1 iulie 2013 23:32:47 |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.44 kb |
#include <cstdio>
using namespace std;
int v[1000001];
int main(){
freopen("fractii.in", "r", stdin);
freopen("fractii.out", "w", stdout);
int n, i, j;
long long suma=0;
scanf("%d", &n);
for(i=2; i<=n; i++) {
v[i]=i-1;
}
for(i=2; i<=n; i++){
suma=suma+v[i];
for(j=2*i; j<=n; j=j+i) v[j]=v[j]-v[i];
}
printf ("%lld\n",suma*2+1 );
return 0;
}