main(i){ int n; scanf("%d",&n); for(i='';~i&' ';){ if(!(n%i)){ puts("NO"); return !i; } if(~i&'')i^=''; else if(~i&'')i^=''; else if(~i&'')i^=''; else if(~i&'')i^=''; else if(~i&'')i^=''; else if(~i&' ')i^='?'; } puts("YES"); }