#include<iostream>
main(){int n=10,a=0,b=1,c=0,d=0;while(n<10000){std::cout<<n<<"\n";a+=1;if(a>=b){a=0;b+=1;};if(c!=0&&b>=c||b>9){a=0;b=1;c+=1;if(c<2){c=2;}};if(d!=0&&c>=d||c>9){a=0;b=1;c=2;d+=1;if(d<3){d=3;}};n=d*1000+c*100+b*10+a;}}