import std.stdio;
import std.conv;
import std.string;
import std.typecons;
import std.algorithm;
import std.array;
import std.range;
import std.math;
import std.regex : regex;
import std.container;

void main()
{
	immutable MAX = 1000000;

	bool p[MAX];
	p[] = 1;
	p[0..1] = 0;
	foreach (i; 2..sqrt(MAX*1.0).ceil.to!int) {
		if (p[i]) {
			foreach (j; iota(i*2, MAX, i))
				p[j] = 0;
		}
	}

	int[] ps;
	foreach (i; 2..MAX) {
		if (p[i]) ps ~= i;
	}

	int n;
	while (n = readln.chomp.to!int, n) {
		int sum;
		ps[0..n].reduce!("a+b").writeln;
	}
}