10394.cpp

/* Problem:  Twin Primes   UVa 10394
   Programmer: Md. Mahmud Ahsan
   Description: Prime Number
   Compiled: Visual C++ 7.0
   Date: 13-08-05
*/
#include <iostream>
#include <string>
#include <cmath>
using namespace std;

#define max 20000000
char seive[max];
int prime[100002];

//modified seive of eratosthenes
void genSeive(){
	int i, j, sq;
	seive[0] =seive[1] = 1;
	sq = sqrt( (double) max);
	for (i = 2; i <= sq; ++i){
		if (!seive[i]){
			for (j = i * i; j < max; j+=i)
				seive[j] = 1;
		}
	}
	//for twin prime modification
	j = 0;
	for (i = 2; i < max; ++i){
		if (!seive[i] && !seive[i + 2])
			prime[++j] = i;
		if (j == 100001) break;
	}
}



int main(){
	genSeive();
	int n;
	while (cin >> n){
		cout << "(" << prime[n] << ", " << prime[n] + 2 << ")" << endl; 
	}
	return 0;
}