#include <stdio.h>
 int main() 
 {
 int x, i, j; 
 // prompt user for input
 printf("%s", "Enter an integer in the range 1-20:");
 scanf("%d", &x); // read values for x
 for (i = 1; i <= x; i++) { // count from 1 to x
 for (j = 1; j <= x; j++) { // count from 1 to x
 if (j==i) 
 printf("%c",'@'); // output @
 else
 printf(" "); 
 } // end inner for
 printf("\n");
 } // end outer for 
 } // end of main