Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

var scanner = bufio.NewScanner(os.Stdin)

const (
	MAX  = 1000000
	SQRT = 1000
)

func main() {
	comp := make([]int, MAX+2)
	sieve := func() {
		for i := 3; i < SQRT; i += 2 {
			if comp[i] == 0 {
				for j := i * i; j < MAX; j += i {
					comp[j] = 1
				}
			}
		}
	}
	sieve()
	tbl := make([]int, MAX+2)
	tbl[2] = 1
	k := 1
	for i := 3; i < MAX; i += 2 {
		if comp[i] == 0 {
			k++
		}
		tbl[i+1], tbl[i] = k, k
	}
	for scanner.Scan() {
		n, _ := strconv.Atoi(scanner.Text())
		if n == 0 {
			break
		}
		ans := 0
		for i := 0; i < n; i++ {
			scanner.Scan()
			buf := strings.Split(scanner.Text(), " ")
			p, _ := strconv.Atoi(buf[0])
			m, _ := strconv.Atoi(buf[1])
			a, b := p-m, p+m
			if a < 2 {
				a = 2
			}
			if b > MAX {
				b = MAX
			}
			ans += tbl[b] - tbl[a-1] - 1
		}
		if ans < 0 {
			ans = 0
		}
		fmt.Println(ans)
	}
}

C++: #include <bits/stdc++.h>

using namespace std;

typedef vector<int> vi;
typedef vector<vi> vii;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<vb> vbb;
typedef pair<int, int> pii;
typedef long long ll;
typedef unsigned long long ull;

#define all(a)  (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair

#define loop(i,a,b) for(int i=(a);i<ull(b);++i)
#define rep(i,n) loop(i,0,n)

const double eps = 1e-10;
const double pi  = acos(-1.0);
const double inf = (int)1e8;

/*素数判定*/
const int MAX = 1000100;
bool prime[MAX];

void sieve(){
    fill(prime, prime+MAX, true);
    prime[0] = prime[1] = false;

    for(int i=0; i < MAX; i++){
            if(!prime[i]) continue;
            for(int j=i+i; j < MAX; j += i){
                        prime[j] = false;
                    }
        }
}

int main(){
    sieve();
    int n;
    while(cin >> n, n){
        int ans = 0;
        for(int i=0; i< n; i++){
            int a, b;
            cin >> a >> b;
            for(int j = a-b; j <= min(a+b, 999983); j++){
                if(prime[j]) ans++;
            }
            ans--;
        }
        cout << ans << endl;
    }
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>

using namespace std;

#define rep(i,j) REP((i), 0, (j))
#define REP(i,j,k) for(int i=(j);(i)<(k);++i)
#define BW(a,x,b) ((a)<=(x)&&(x)<=(b))
#define F first
#define S second
#define INF 1 << 30
#define MAX_P 1000000

typedef pair<int, int> pi;
typedef pair<int, pi> pii;
typedef vector<int> vi;
typedef queue<int> qi;
typedef long long ll;


int p[MAX_P], n;

int main(){
  p[0] = p[1] = 1;
  REP(i, 2, MAX_P/2){
    if(!p[i]){
      for(int j = i+i; j < MAX_P; j += i) p[j] = 1;
    }
  }
  //  rep(i, 100) if(!p[i])printf("%d ", i); puts("");

  while(scanf("%d", &n) && n){
    int ip, m, res = 0;
    rep(i, n){
      scanf("%d%d", &ip, &m);
      int c = 0;
      REP(j, (ip-m)>0?(ip-m):0, (ip+m+1)>MAX_P?MAX_P:(ip+m+1)) if(!p[j]) c++;
      if(c) res += c-1;
      else res--;
    }
    printf("%d\n", res);
  }
  return 0;
}

C++: #include<iostream>
#include<cmath>
#include<vector>
#include<algorithm>
#define REP(i,s,n) for(int i=s;i<n;i++)
#define rep(i,n)   REP(i,0,n)
#define inf (1<<29)
#define all(n) (n).begin(),(n).end()
#define MAX 1000004
using namespace std;

vector<int> prime;
bool isntprime[MAX+1]; 
void init()
{	
  isntprime[0] = isntprime[1] = true;
  int j;	
  for(int i=2;i<= MAX;i++)if(!isntprime[i])for(prime.push_back(i),j=2*i;j<=MAX;j+=i)isntprime[j] = true;
}

int main()
{
  init();
  int n;
  while(cin >> n,n)
    {
      int p,m;
      int ans = n/101;
      rep(i,n)
	{
	  cin >> p >> m;
	  int bottom = max(0,p-m);
	  int top = min(999983,p+m);
	  int X = upper_bound(all(prime),top) - lower_bound(all(prime),bottom);
	  if(X == 0)ans--;
	  else      ans += X-1;
	}
      cout << ans << endl;
    }
  return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;

vector<int>primes(1e6);
vector<int>sums(1e6 + 1);
void hurui(const int amax) {
	static bool flag = false;
	if (flag)return;
	vector<int>sos;
	sos = vector<int>(amax + 1, true);
	sos[0] = false; sos[1] = false;
	for (int i = 2; i <= amax; ++i) {
		if (sos[i]) {
			for (int j = 2 * i; j <= amax; j += i)sos[j] = false;
		}
	}
	for (int i = 0; i <= amax; ++i) {
		if (sos[i]) {
			primes[i] = true;
		}
	}
	flag = true;
}


int main() {
	hurui(999983);
	for (int i = 0; i < 1e7; ++i) {
		sums[i + 1] = sums[i] + primes[i + 1];
	}
	while (1) {
		int N; cin >> N;
		if (!N)break;
		long long int prize = 0;
		while (N--) {
			long long int p, m; cin >> p >> m;
			int amax = min(999983ll, p + m);
			int amin = max(0ll, p - m-1);
			const int aprize = sums[amax] - sums[amin];
			prize += aprize - 1;
		}
		cout << max(0ll,prize )<< endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std ;

#define pb(n) push_back(n)
#define fi first
#define se second
#define all(r) (r).begin(),(r).end()
#define gsort(st,en) sort((st),(en),greater<int>())
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout<<#x<<": "<<x<<endl
#define fcout(n) cout<<fixed<<setprecision((n))
#define scout(n) cout<<setw(n)
#define vary(type,name,size,init) vector< type> name(size,init)

#define rep(i,n) for(int i = 0; i < (int)(n);++i)
#define REP(i,a,b) for(int i = (a);i < (int)(b);++i)
#define repi(it,array) for(auto it = array.begin(),end = array.end(); it != end;++it)
#define repa(n,array) for(auto &n :(array))

using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using dict = map<string,int>;
using pii = pair<int,int> ;

constexpr int imax = ((1<<30)-1)*2+1 ;
constexpr int inf = 100000000;
constexpr double PI = acos(-1.0) ;
double eps = 1e-10 ;
const int dy[] = {-1,0,1,0};
const int dx[] = {0,-1,0,1};

inline bool value(int x,int y,int w,int h){
  return (x >= 0 && x < w && y >= 0 && y < h);
}

template<typename T>
void Unique(vector<T> &v){
  sort(all(v));
  v.erase(unique(all(v)),v.end());
}

template<typename T>
T ston(string& str, T n){
  istringstream sin(str) ;
  T num ;
  sin >> num ;
  return num ;
}

void Ans(bool f){
  if(f) cout << "YES"<<endl;
  else cout << "NO"<<endl;
}

const int PrimeMax = 999984;
int is_prime[PrimeMax],sum[PrimeMax];
void Eratosthenes(int N){
  for(int i = 0; i < N; i++){
    is_prime[i] = 1;
  }
  is_prime[0] = 0;
  is_prime[1] = 0;
  for(int i = 2; i*i < N ; i++){
    if(is_prime[i]){
      for(int j = 0; i * (j + 2) < N; j++){
        is_prime[i *(j + 2)] = 0;
      }
    }
  }
  REP(i,0,N){
    sum[i+1] += sum[i] + is_prime[i];
  }
}
int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n;
  Eratosthenes(PrimeMax);
  while(cin>>n && n){
    ll p,m,ans = 0;
    rep(i,n){
      ll f,s;
      cin >> p>>m;
      s = max(0LL,p-m-1);
      f = (p+m > PrimeMax) ? PrimeMax: p + m;
      ans += (sum[f]-sum[s])-1;
    }
    cout << ans << endl;
  }
  return 0;
}