#include <stdio.h>

main(){

int board = 0;
int i;
int j;
int k;
k = 0;
printf("How bif do you want the square");
scanf("%d", &board);



for(i = 0; i<board; i++){
	for(j = 0; j<board; j++){
		if(k == 0){
		printf("_");
		k = 1;
		}
		else{
			if(k == 1){
			printf("#");
			k = 0;
			}
		}
	}
	printf("\n");
}



return 0;
}