a = []
n = input().split(' ')
d = int(n[1])
n = int(n[0])
x = input().split(' ')
k=0
for i in range(n):
a.append(int(x[i]))
if (i>0 and a[i-1] >= a[i]):
k += ((a[i - 1] - a[i]) // d) + 1
a[i] += ((a[i - 1] - a[i]) // d) * d + d
print(k)
1191A - Tokitsukaze and Enhancement | 903A - Hungry Student Problem |
52B - Right Triangles | 1712A - Wonderful Permutation |
1712D - Empty Graph | 1712B - Woeful Permutation |
1712C - Sort Zero | 1028B - Unnatural Conditions |
735B - Urbanization | 746C - Tram |
1278B - A and B | 1353D - Constructing the Array |
1269C - Long Beautiful Integer | 1076A - Minimizing the String |
913C - Party Lemonade | 1313A - Fast Food Restaurant |
681A - A Good Contest | 1585F - Non-equal Neighbours |
747A - Display Size | 285A - Slightly Decreasing Permutations |
515C - Drazil and Factorial | 1151E - Number of Components |
1151F - Sonya and Informatics | 556A - Case of the Zeros and Ones |
867A - Between the Offices | 1569A - Balanced Substring |
260A - Adding Digits | 1698C - 3SUM Closure |
1029B - Creating the Contest | 1421A - XORwice |