#define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define IOS ios::sync_with_stdio(false); cin.tie(0); #define FOR(i, s, n) for(int i = (s), i##_len=(n); i < i##_len; ++i) #define FORS(i, s, n) for(int i = (s), i##_len=(n); i <= i##_len; ++i) #define VFOR(i, s, n) for(int i = (s); i < (n); ++i) #define VFORS(i, s, n) for(int i = (s); i <= (n); ++i) #define REP(i, n) FOR(i, 0, n) #define REPS(i, n) FORS(i, 0, n) #define VREP(i, n) VFOR(i, 0, n) #define VREPS(i, n) VFORS(i, 0, n) #define RFOR(i, s, n) for(int i = (s), i##_len=(n); i >= i##_len; --i) #define RFORS(i, s, n) for(int i = (s), i##_len=(n); i > i##_len; --i) #define RREP(i, n) RFOR(i, n, 0) #define RREPS(i, n) RFORS(i, n, 0) #define ALL(v) (v).begin(), (v).end() #define SORT(v) sort(ALL(v)) #define RSORT(v) sort(ALL(v), greater()) #define SZ(x) ((int)(x).size()) #define PB push_back #define EB emplace_back #define MP make_pair #define MT make_tuple #define BIT(n) (1LL<<(n)) #define UNIQUE(v) v.erase(unique(ALL(v)), v.end()) using ll = long long; using ui = unsigned int; using ull = unsigned long long; using Pi_i = pair; using VB = vector; using VC = vector; using VD = vector; using VI = vector; using VLL = vector; using VS = vector; using VSH = vector; using VULL = vector; const int MOD = 1000000007; const int INF = 1000000000; const int NIL = -1; template bool chmax(T &a, const S &b){ if(a < b){ a = b; return true; } return false; } template bool chmin(T &a, const S &b){ if(b < a){ a = b; return true; } return false; } VB isPrime; void Eratosthenes(int n){ if(n + 1 <= SZ(isPrime)) return; isPrime.resize(n+1, true); isPrime[0] = isPrime[1] = false; for(int i = 2; i * i <= n; ++i){ if(isPrime[i]){ for(int j = i; i * j <= n; ++j) isPrime[i*j] = false; } } } int main(){ int N; cin >> N; Eratosthenes(N); int sum = 0; REPS(i, N){ if(isPrime[i]) sum += i; } cout << sum << endl; return 0; }