#include <stdio.h>

main()
{
	int i = 1, j;
	
	while(i <= 20){
		j = 1;
		
		while(j <= i){
			printf("%3d", j);
			
			if(j == i)
				printf("\n");
			j++;
			
		}
		
		i++;
	}

	printf("\n");
	
	return(0);
	
}