C :

#include<stdio.h>

int main()
{
	printf("A\n");
	printf("BC\n");
	printf("DEF\n");
	printf("GHIJ\n");
	printf("KLMNO\n");
	printf("PQRSTU\n");
	printf("V\n");
	printf("W\n");
	printf("X\n");
	printf("Y\n");
	printf("Z\n");
	return 0;
}

C++ :

#include<stdio.h>

int main()
{
	printf("A\n");
	printf("BC\n");
	printf("DEF\n");
	printf("GHIJ\n");
	printf("KLMNO\n");
	printf("PQRSTU\n");
	printf("V\n");
	printf("W\n");
	printf("X\n");
	printf("Y\n");
	printf("Z\n");
	return 0;
}