#include<cstdio>
#define MAXN 2000001
int a[MAXN],i,j;
int main() {
	int m;
	while(scanf("%d",&m) == 1 && m!=0) {
		for(i = 2; i <= m; i++)
			a[i] =i;
		for(i = 2; i <= m/2; i++) {
			if(a[i] != 0) {
				for(j=i+i; j <= m; j += i) {
					a[j] = 0;
				}
			}
		}
		for(i = 2; i <= m; i++) {
			if(a[i] != 0) printf("%d\n",a[i]);
		}
	}
	return 0;
}