An atom of element X can exist in *n* distinct states with energies *E*<sub class="lower-index">1</sub> &lt; *E*<sub class="lower-index">2</sub> &lt; ... &lt; *E*<sub class="lower-index">*n*</sub>. Arkady wants to build a laser on this element, using a three-level scheme. Here is a simplified description of the scheme. 

Three distinct states *i*, *j* and *k* are selected, where *i* &lt; *j* &lt; *k*. After that the following process happens: 
 1.  initially the atom is in the state *i*,1.  we spend *E*<sub class="lower-index">*k*</sub> - *E*<sub class="lower-index">*i*</sub> energy to put the atom in the state *k*,1.  the atom emits a photon with useful energy *E*<sub class="lower-index">*k*</sub> - *E*<sub class="lower-index">*j*</sub> and changes its state to the state *j*,1.  the atom spontaneously changes its state to the state *i*, losing energy *E*<sub class="lower-index">*j*</sub> - *E*<sub class="lower-index">*i*</sub>,1.  the process repeats from step 1. 
Let's define the energy conversion efficiency as <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/b1353c834ae20a0534a47916c2f0fbe98d7f4b7c.png" style="max-width: 100.0%;max-height: 100.0%;"/>, i. e. the ration between the useful energy of the photon and spent energy.

Due to some limitations, Arkady can only choose such three states that *E*<sub class="lower-index">*k*</sub> - *E*<sub class="lower-index">*i*</sub> ≤ *U*.

Help Arkady to find such the maximum possible energy conversion efficiency within the above constraints.
The first line contains two integers *n* and *U* (3 ≤ *n* ≤ 10<sup class="upper-index">5</sup>, 1 ≤ *U* ≤ 10<sup class="upper-index">9</sup>) — the number of states and the maximum possible difference between *E*<sub class="lower-index">*k*</sub> and *E*<sub class="lower-index">*i*</sub>.

The second line contains a sequence of integers *E*<sub class="lower-index">1</sub>, *E*<sub class="lower-index">2</sub>, ..., *E*<sub class="lower-index">*n*</sub> (1 ≤ *E*<sub class="lower-index">1</sub> &lt; *E*<sub class="lower-index">2</sub>... &lt; *E*<sub class="lower-index">*n*</sub> ≤ 10<sup class="upper-index">9</sup>). It is guaranteed that all *E*<sub class="lower-index">*i*</sub> are given in increasing order.
In the first example choose states 1, 2 and 3, so that the energy conversion efficiency becomes equal to <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/147ae7a830722917b0aa37d064df8eb74cfefb97.png" style="max-width: 100.0%;max-height: 100.0%;"/>.

In the second example choose states 4, 5 and 9, so that the energy conversion efficiency becomes equal to <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/f68f268de4eb2242167e6ec64e6b8aa60a5703ae.png" style="max-width: 100.0%;max-height: 100.0%;"/>.
4 4
1 3 5 7
0.5
10 8
10 13 15 16 17 19 20 22 24 25
0.875
3 1
2 5 10
-1
5 3
4 6 8 9 10
0.5
10 128
110 121 140 158 174 188 251 271 272 277
0.86554621848739499157
20 17
104 107 121 131 138 140 143 144 178 192 193 198 201 206 238 242 245 248 255 265
0.92857142857142860315
30 23
102 104 105 107 108 109 110 111 116 118 119 122 127 139 140 142 145 157 166 171 173 174 175 181 187 190 191 193 195 196
0.95652173913043481157
50 64
257 258 350 375 1014 1017 1051 1097 1169 1177 1223 1836 1942 1983 2111 2131 2341 2418 2593 2902 2948 3157 3243 3523 3566 4079 4499 4754 5060 5624 6279 6976 7011 7071 7278 7366 7408 7466 7526 7837 7934 8532 8577 8680 9221 9271 9327 9411 9590 9794
0.91891891891891896993
5 2
4 6 8 9 10
0.5
10 2
110 121 140 158 174 188 251 271 272 277
-1
30 5
102 104 105 107 108 109 110 111 116 118 119 122 127 139 140 142 145 157 166 171 173 174 175 181 187 190 191 193 195 196
0.80000000000000004441
10 6
110 121 140 158 174 188 251 271 272 277
0.83333333333333337034
20 4
104 107 121 131 138 140 143 144 178 192 193 198 201 206 238 242 245 248 255 265
0.25
3 1000000000
1 2 1000000000
0.99999999900000002828
3 1
1 2 3
-1
5 1000000000
1 2 3 999999999 1000000000
0.99999999900000002828
10 199
1 3 190 191 193 195 196 197 199 200
0.98994974874371854945
10 300
80 100 103 140 146 159 392 393 396 398
0.98993288590604022747
10 92
44 119 252 281 303 323 351 363 377 392
0.77528089887640450062
4 2
1 3 5 7
-1
8 2
1 3 7 9 15 17 23 25
-1
3 5
1 2 10
-1
4 7
1 5 8 9
0.42857142857142854764
n, u = map(int, input().split())
E = list(map(int, input().split()))
p0 = -1
q0 = -1
ind = 0
for k in range(2, n):
    ei = E[k] - u
    while ind < n and E[ind] < ei:
        ind += 1
    if ind + 1 < k and E[k]-E[ind] <= u:
        p = E[k]-E[ind+1];
        q = E[k]-E[ind];
        if p0 == -1:
            p0 = p
            q0 = q
        else if p*q0 >= p0*q:
            p0 = p
            q0 = q
if p0 == -1:
    print(-1)
eles:
    print(p0 /q0)
        