Cod sursa(job #241402)

Utilizator nusmaibunkeleviprofesor cicalescu nusmaibunkelevi Data 9 ianuarie 2009 23:27:53
Problema Fractii Scor 30
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.34 kb
Raporteaza aceasta sursa 
#include<stdio.h>

int main(){
freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);
long long n,i,j,fi,r,nr;
scanf("%d",&n);
r=1;
for(i=2;i<=n;++i){
	nr=i;fi=nr;
	for(j=2;j*j<=nr;++j){
		if(nr%j==0) fi=(fi*(j-1))/j;
		while(nr%j==0) nr=nr/j;
		}
	if(nr>1) fi=(fi*(nr-1))/nr;
	r=r+2*fi;
	}
printf("%d",r);
return 0;
}