1 #include <iomanip>
2 #include <iostream>
3 #include <cstdio>
4 #include <cmath>
5 #include <cstring>
6 #include <algorithm>
7 #include <queue>
8 #include <stack>
9 #include <vector>
10 #include <map>
11 using namespace std;
12 int sushu(int k)
13 {
14 double m=sqrt(k+1.0);
15 for(int i=2;i<=m;i++)
16 {
17 if(k%i==0)
18 return 0;
19 }
20 return 1;
21 }
22 int main(int argc, char *argv[])
23 {
24 int n,ans;
25 ans=0;
26 while(scanf("%d",&n)!=EOF)
27 {
28 ans++;
29 if(n<=0)
30 break;
31 printf("%d: ",ans);
32 if(n==1||n==2)
33 {
34 printf("no\n");
35 continue;
36 }
37 int t=sushu(n);
38 if(t==1)
39 printf("yes\n");
40 else
41 printf("no\n");
42 }
43 return 0;
44 }
45
