# include <cmath> # include <cstring> # include <iostream> const int MAXN =1000000; int n; int f1[MAXN], f2[MAXN],f3[MAXN]; int calc_f1(int x) { int ans=1; int maxNum = sqrt(x); for (int i= 2; i<= maxNum; ++i) if(x%i==0) { ans=-ans; x/=i; if (x%i== 0) return 0; } if(x!=1) ans =-ans; return ans; } int calc_f2(int x) { return x; } void convolute( ) { memset(f3, 0, sizeof(f3)); for (int i = 1; i<= n; ++i) for (int j= 1; j<= n/i; ++j) if(i*j<=n) f3[i*j]= f3[i* i]+ f1[i]*f2[j]; } int main() { scanf("%d", &n); for (int i= 1; i<= n; ++i) f1[i] = calc_f1(i); for (int i= 1; i<= n; ++i) f2[i] - calc_f2(i); convolute(); printf("% d\backslashn", f3[n]); return 0; }