Pta: self test -2 prime pair conjecture (20 points)

 The basic idea ： Find all prime pairs first , Then go through it to see how many pairs there are .

#include"stdio.h"
#include"math.h"
#include <cstdlib>
#include <iostream>
#include <queue>

using namespace std;

int sushu(int n)
{
    
	int i=2;
	if(n<2) return 0;
	for(;i<=sqrt(n);i++){
    
		if(n%i==0){
    
			return 0;
		}
	}
	return 1;
}

int main(){
    	
	queue<int> q;
	int n =0;
	scanf("%d",&n);
	int m =0;
	int s = 2;
	for (int i=3;i<=n;i++){
    
		if(sushu(i) == 1){
    
			if((i-s) == 2){
    
				m++;
			}
			s =i;
		}
		
	}
	printf("%d",m);
}