usaco sprime

/*ID: ljracm1LANG: C++PROB: sprime*/#include<iostream>#include<math.h>#include<cstdio>#define Tusing namespace std;int n;int s[10];int judge(int x){    for(int i=2; i<=sqrt(x); i++)        if(x%i==0)return false;    return true;}void dfs(int d,int num){   int tem;   for(int i=0; i<6; i++){        if(d==1&&i==0)continue;        tem = num*10+s[i];        if(judge(tem)){            if(d==n)                cout<<tem<<endl;            else                dfs(d+1,tem);        }   }}int main(){   #ifdef T       freopen("sprime.in","r",stdin);       freopen("sprime.out","w",stdout);   #endif   cin>>n;   s[0]=1; s[1]=2; s[2]=3;   s[3]=5; s[4]=7; s[5]=9;   dfs(1,0);   return 0;}