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<iostream>
#include<vector>
#include<algorithm>

using namespace std;

const int MAX = 1000000;
bool prime[MAX];
vector<int> V;
int ans;

void make(){
  fill(prime,prime+MAX,1);
  prime[0] = prime[1] = 0;
  for(int i = 2; i*i < MAX; i++)
    if(prime[i])
      for(int j = 2*i; j < MAX; j+=i)
	prime[j] = 0;

  V.push_back(2);
  for(int i = 3; i < MAX; i+=2)
    if(prime[i]) V.push_back(i);

}

int solve(int p, int m){
  int num = upper_bound(V.begin(),V.end(),p+m)-
    lower_bound(V.begin(),V.end(),p-m);
  return num-1;
}
int main(){
  make();
  int num;
  while(cin >> num && num){
    ans = 0;
    for(int i = 0; i < num; i++){
      int p,m;
      cin >> p >> m;
      ans += solve(p,m);
    }
    cout << ans << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <vector>
#include <cmath>
using namespace std;

#define N 1000000

int main(void){
	vector<bool> isprime(N+1);
	for(int i=0;i<isprime.size();i++) isprime[i]=true;
	int upto = (int)sqrt(isprime.size());
	isprime[0]=isprime[1]=false;
	for(int i=2;i<=upto;++i){
		if(isprime[i]){//消されてなければその倍数を消す
			for(int j=2;i*j<isprime.size();++j) isprime[i*j] = false;
		}
	}
	vector<int> s(N+1,0);
	for(int i=0;i<N;++i) s[i+1]+=s[i]+((isprime[i+1])?1:0);
	int n;
	while(cin>>n,n){
		int ans=0;
		for(int i=0,p,m,x=0;i<n;++i){
			cin>>p>>m;
			x=s[(p+m>N)?N:p+m]-s[(p-m<0)?0:p-m]+isprime[(p-m<0)?0:p-m];
			ans+=x-1;
		}
		cout<<ans<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include <algorithm>
#include<functional>//greaterの使用
using namespace std;
#define MAX_LIST 999983+100
#define MP 999983

int main(){
	bool prime[MAX_LIST];
	for(int i=0;i<MAX_LIST;i++){
		prime[i]=1;
	}
	prime[0]=prime[1]=0;
	for(int i=0;i*i<MAX_LIST;i++){
		if(prime[i]==1){
			for(int j=i*2;j<MAX_LIST;j=j+i){
				prime[j]=0;
			}
		}
	}
	for(int i=MP+1;i<MAX_LIST;i++){
		prime[i]=0;
	}
	
	int prime_num[MAX_LIST];
	prime_num[0]=1;
	for(int i=1;i<MP;i++){
		prime_num[i]=prime_num[i-1]+prime[i];
	}
	
	
	int pair_num;
	while(cin>>pair_num,pair_num){
		int ans=0;
		for(;pair_num--;){
			int p,m;
			int x;
			cin>>p;
			cin>>m;
			
			if(p+m>MP){
				x=prime_num[MP]-prime_num[p-m];
			}else{
				x=prime_num[p+m]-prime_num[p-m];
			}
			
			if(x<0){
				ans--;
			}else{
				ans=ans+x;
			}
		}
		cout<<ans<<endl;
	}
	return 0;
}

C++: //include
//------------------------------------------
#include <bits/stdc++.h> // only for GCC

using namespace std;

//typedef
//------------------------------------------
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef pair<int, int> pii;
typedef long long ll;
typedef unsigned long long ull;

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

//repetition
//------------------------------------------
#define loop(i,a,b) for(ull i=(a);i<ull(b);++i)
#define rep(i,n) loop(i,0,n)
#define iter(i,c) for(auto i=(c).begin(); i!=(c).end(); ++i)
#define riter(i,c) for(auto i=(c).rbegin(); i!=(c).rend(); ++i)

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

// output vector
// ------------------------------------------
namespace std {
    template<typename T>ostream&operator<<(ostream&os, vector<T>const&v){
        iter(it,v) os<<*it<<(it+1==v.end()?"":",");
        return os;
    }
    template<typename T, typename U>ostream&operator<<(ostream&os,const pair<T,U>&p){
        return os << "[" << p.dirst << "," << p.second << "]";
    }
}

//clear memory
// ------------------------------------------
#define clr(a,i) memset((a), (i) ,sizeof(a))

int lcm(int a,int b){
   return a*b/__gcd(a,b);
}
 
vb pn(1000001,1); 
void prime_number(ull n){
   //fill(all(pn),1);
   pn[0]=false;pn[1]=false;
   loop(i,2,n/2+1){
      if(!pn[i]) continue;
      for(ull j=2;i*j<=n;j++){
         pn[i*j]=false;
      }
   }
}

int main(){
   ull n,s,g;
   ll p,m;
   int x;
   prime_number(999983);
   while(cin >> n&&n){
      x=0;
      rep(i,n){
         cin>>p>>m;
         if(p-m<2) s=2;
         else s=p-m;
         if(p+m>999983) g=999984;
         else g=p+m+1;
         x+=(count(pn.begin()+s,pn.begin()+g,1)-1);
      }
      cout << x << endl;
   }
   return 0;
}

C++: #include <iostream>
#include <algorithm>
using namespace std;
int n, m, p, prime[1000009], s[1000009];
int main() {
	fill(prime + 2, prime + 1000000, 1);
	for (int i = 2; i < 1000; i++) {
		if (!prime[i]) continue;
		for (int j = i * i; j < 1000000; j += i) prime[j] = 0;
	}
	for (int i = 2; i < 1000009; i++) s[i] = s[i - 1] + prime[i];
	while (cin >> n, n) {
		int ret = 0;
		for (int i = 0; i < n; i++) {
			cin >> p >> m;
			ret += s[min(p + m + 1, 1000000)] - s[max(p - m, 0)] - 1;
		}
		cout << ret << endl;
	}
}

C++: #include <stdio.h>
#include <cmath>
#include <algorithm>
#include <cfloat>
#include <stack>
#include <queue>
#include <vector>
#include <string>
#include <iostream>
typedef long long int ll;
typedef unsigned long long int ull;
#define BIG_NUM 2000000000
#define MOD 1000000007
#define EPS 0.000000001
using namespace std;

#define NUM 999986

int* table,*ruisekiwa;
int N;

void func(){

	int prime,m,left,right;
	int to_people = 0,to_king = 0,tmp;

	for(int i = 0; i < N; i++){
		scanf("%d %d",&prime,&m);

		left = ruisekiwa[max(0,prime-m-1)];
		if(prime-m > NUM){
			left = ruisekiwa[NUM-1];
			right = ruisekiwa[NUM-1];
		}else if(prime+m >= NUM){
			right = ruisekiwa[NUM-1];
		}else{
			right = ruisekiwa[prime+m];
		}

		tmp = right - left;
		if(tmp == 0)to_king++;
		else{
			to_people += tmp-1;
		}
	}

	printf("%d\n",to_people-to_king);

}

int main(){

	table = new int[NUM];
	ruisekiwa = new int[NUM];

	for(int i = 0; i < NUM; i++){
		table[i] = 0;
		ruisekiwa[i] = 0;
	}

	int limit = sqrt(NUM);

	for(int i = 2; i <= limit; i++){
		if(table[i] == 0){
			for(int j = 2*i; j < NUM; j+=i){
				table[j] = 1;
			}
		}
	}

	for(int i = 2; i < NUM; i++){
		if(table[i] == 0){
			ruisekiwa[i] = 1;
		}
	}

	for(int i = 3; i < NUM; i++){
		ruisekiwa[i] += ruisekiwa[i-1];
	}

	while(true){
		scanf("%d",&N);
		if(N == 0)break;

		func();
	}

	return 0;
}