UVA 10948 The primary problem

/***
	Md. Nazmul Hasan
	Shahjalal University of Science & Technology,Sylhet.
	hasan08sust@gmail.com
	***/
	#include<iostream>
	#include<cstdio>
	#include<stack>
	#include<queue>
	#include<map>
	#include<vector>
	#include<algorithm>
	#include<cstring>
	#include<sstream>
	#include<cmath>
	#include <iomanip>
	using namespace std ;
	typedef long long ll ;
	typedef int in ;
	typedef unsigned long long ull ;
	const double pi = 2*acos(0) ;
	#define maxi 1000001
	#define pf printf
	#define sc scanf
	#define pb push_back
	#define MEM(x,y) (memset((x),(y),sizeof(x)))
	#define MIN(x,y) ((x) < (y) ? (x) : (y))
	#define MAX(x,y) ((x) > (y) ? (x) : (y))
	#define load(array,size) for(int i=0 ; i<size ; i++) cin>>array[i] ;
	#define new_line pf("\n")
	#define clear_data(array) memset(array,0,sizeof(array))
	#define highest_int 2147483647
	bool isPrime[maxi];
	vector<int> data;
	int x,n;
	void sieve(){
	memset(isPrime,true , sizeof(isPrime));
	isPrime[0] = isPrime[1] = false;
	for(int i=4 ; i<=maxi ; i+=2){
	isPrime[i] = false;
	}
	for(int i=3 ; i*i<maxi ; i+=2){
	if(isPrime[i]){
	for(int j=i*i ; j<maxi ; j+=i+i)
	isPrime[j] = false;
	}
	}
	data.pb(2);
	for(int i=3 ; i<maxi ; i+=2)
	if(isPrime[i])
	data.pb(i);
	}
	bool check(){
	if(n%2 || n==4){
	x =2 ;
	return isPrime[n-x];
	}
	for(int i=1 ; i<data.size() && data[i]<=n/2 ; i++){
	if(isPrime[n-data[i]]){
	x = data[i];
	return true;
	}
	}
	return false;
	}
	int main()
	{
	sieve();
	while(sc("%d",&n) && n){
	pf("%d:\n",n);
	if(check()){
	pf("%d+%d\n",x,n-x);
	}else{
	pf("NO WAY!\n");
	}
	}
	return 0;
	}