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Given two integers** ‘a’ **and** ‘m**’. The task is to find the smallest modular multiplicative inverse of **‘a’** under modulo** ‘m’**.

**Example 1:**

**Input:
**a = 3
m = 11
**Output: **4
**Explanation: **Since (4*3) mod 11 = 1, 4
is modulo inverse of 3. One might think,
15 also as a valid output as "(15*3)
mod 11" is also 1, but 15 is not in
ring {0, 1, 2, ... 10}, so not valid.

**Example 2:**

**Input:
**a = 10
m = 17
**Output: **12
**Explanation: **Since (12*10) mod 17 = 1,
12 is the modulo inverse of 10.

**Your Task:**

You don't need to read input or print anything. Your task is to complete the function** ** **function modInverse() **that takes **a and m as input parameters **and **returns **modular multiplicative inverse of **‘a’** under modulo** ‘m’**. If the modular multiplicative inverse doesn't exist **return -1.**

**Expected Time Complexity** : O(m)

**Expected Auxilliary Space** : O(1)

**Constraints:**

1 <= a <= 10^{4}

1 <= m <= 10^{4}

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Modular Multiplicative Inverse

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