Cod sursa(job #766186)
Utilizator | Data | 10 iulie 2012 15:45:13 | |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.34 kb |
#include <cstdio>
FILE *f=fopen("fracti.in","r");
FILE *g=fopen("fracti.out","w");
int v[1000001],n,i,j;
int main()
{
long long nr=0;
fscanf(f,"%d",&n);
for (i=1;i<=n;i++)
v[i]=i-1;
for (i=2;i<=n;i++)
{
for (j=i*2;j<=n;j=j+i)
v[j]=v[j]-v[i];
nr=nr+v[i];
}
nr=nr*2+1;
fprintf(g,"%lld",nr);
fclose(f);
return 0;
}