#include <bits/stdc++.h>
using namespace std;
#define SIZE 10000
vector <int> prime;
char stat[SIZE];
int Sieve(int x){
int i,j;
int s=sqrt(x);
prime.push_back(2);
for(i=3;i<=s;i++){
if(stat[i]==0){
for(j=i*i;j<=x;j++){
stat[j]==1;
}
}
}
for(i=3;i<=x;i++){
if(stat[i]==0){
prime.push_back(i);
cout<<i;
}
}
}
int main() {
int n;
while(scanf("%d",&n)!=EOF){
Sieve(n);
}
return 0;
}
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