Program for merge sort with time complexity

Program
Time Complexity: O(n log n)

#include <stdio.h>
#include <conio.h>
#include <time.h>
#include <stdlib.h>
void Merge(int a[], int low, int mid, int high)
{
    int i, j, k, b[20];
    i = low;
    j = mid + 1;
    k = low;
    while (i <= mid && j <= high)
    {
        if (a[i] <= a[j])
            b[k++] = a[i++];
        else
            b[k++] = a[j++];
    }
    while (i <= mid)
        b[k++] = a[i++];
    while (j <= high)
        b[k++] = a[j++];
    for (k = low; k <= high; k++)
        a[k] = b[k];
}
void MergeSort(int a[], int low, int high)
{
    int mid;
    if (low >= high)
        return;
    mid = (low + high) / 2;
    MergeSort(a, low, mid);
    MergeSort(a, mid + 1, high);
    Merge(a, low, mid, high);
}
void main()
{
    int n, a[2000], i;
    clock_t st, et;
    double ts;
    printf("*********************************************************");
    printf("\n*********************************************************");
    printf("\n**    WAP for merge sort with time complexity in C     **");
    printf("\n**                Created by Sheetal Garg              **");
    printf("\n**                 Assistant Professor                 **");
    printf("\n**                 Phone No:9467863365                 **");
    printf("\n*********************************************************");
    printf("\n*********************************************************");
    printf("\n Enter How many Numbers:");
    scanf("%d", &n);
    printf("\nEnter array elements\n");
    for (i = 0; i < n; i++)
        scanf("%d", &a[i]);
    st = clock();
    MergeSort(a, 0, n - 1);
    et = clock();
    ts = (double)(et - st) / CLOCKS_PER_SEC;
    printf("\n Sorted Numbers are : \n");
    for (i = 0; i < n; i++)
        printf("%d\n", a[i]);
    printf("\nThe time taken is %e", ts);
}

Output 1

*********************************************************
*********************************************************
**    WAP for merge sort with time complexity in C     **
**                Created by Sheetal Garg              **
**                 Assistant Professor                 **
**                 Phone No:9467863365                 **
*********************************************************
*********************************************************
Enter How many Numbers:8

Enter array elements
12
21
12
23
32
31
14
41

 Sorted Numbers are :
 12
12
14
21
23
31
32
41

The time taken is 0.000000e+000