#include using namespace std; typedef long long ll; typedef pair p_ll; template void debug(T itr1, T itr2) { auto now = itr1; while(now=0; i--) const ll MOD = pow(10,9)+7; const ll LLINF = pow(2,61)-1; const int INF = pow(2,30)-1; vector fac; void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; } ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; } ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; } ll gcd(ll a, ll b) { if (a isp; void sieve(int x=pow(10,6)+10) { isp.resize(x,true); isp[0] = false; isp[1] = false; for (int i=2; pow(i,2)<=x; i++) { if (isp[i]) for(int j=2; i*j<=x; j++) isp[i*j] = false; } } // ---------------------------------------------------------------------- // ---------------------------------------------------------------------- int main() { ll N; cin >> N; sieve(); ll result = 0; for (ll r=0; r*r<=N*2; r++) { if (isp[r]) { rep(p,min(N,r*r)+1) result += isp[p] && isp[r*r-p] && r*r-p<=N; } } cout << result << endl; return 0; }