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Minimum number of given operation required to convert n to m
• Difficulty Level : Medium
• Last Updated : 23 Apr, 2021

Given two integers n and m, in a single operation n can be multiplied by either 2 or 3. The task is to convert n to m with a minimum number of given operations. If it is impossible to convert n to m with the given operation then print -1.
Examples:

Input: n = 120, m = 51840
Output:
120 * 2 * 2 * 2 * 2 * 3 * 3 * 3 = 51840
Input: n = 42, m = 42
Output:
No operation required.
Input: n = 48, m = 72
Output: -1

Approach: If m is not divisible by n then print -1 as n cannot be converted to m with the given operation. Else we can check if, on dividing, the quotient has only 2 and 3 as prime factors. If yes then the result will be the sum of powers of 2 and 3 else print -1
Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Function to return the minimum``// operations required``int` `minOperations(``int` `n, ``int` `m)``{``    ``if` `(m % n != 0)``        ``return` `-1;` `    ``int` `minOperations = 0;``    ``int` `q = m / n;` `    ``// Counting all 2s``    ``while` `(q % 2 == 0) {``        ``q = q / 2;``        ``minOperations++;``    ``}` `    ``// Counting all 3s``    ``while` `(q % 3 == 0) {``        ``q = q / 3;``        ``minOperations++;``    ``}` `    ``// If q contained only 2 and 3``    ``// as the only prime factors``    ``// then it must be 1 now``    ``if` `(q == 1)``        ``return` `minOperations;` `    ``return` `-1;``}` `// Driver code``int` `main()``{``    ``int` `n = 120, m = 51840;``    ``cout << minOperations(n, m);` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``class` `GfG {` `    ``// Function to return the minimum``    ``// operations required``    ``static` `int` `minOperations(``int` `n, ``int` `m)``    ``{``        ``if` `(m % n != ``0``)``            ``return` `-``1``;` `        ``int` `minOperations = ``0``;``        ``int` `q = m / n;` `        ``// Counting all 2s``        ``while` `(q % ``2` `== ``0``) {``            ``q = q / ``2``;``            ``minOperations++;``        ``}` `        ``// Counting all 3s``        ``while` `(q % ``3` `== ``0``) {``            ``q = q / ``3``;``            ``minOperations++;``        ``}` `        ``// If q contained only 2 and 3``        ``// as the only prime factors``        ``// then it must be 1 now``        ``if` `(q == ``1``)``            ``return` `minOperations;` `        ``return` `-``1``;``    ``}` `    ``// Driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``int` `n = ``120``, m = ``51840``;``        ``System.out.println(minOperations(n, m));``    ``}``}`

## Python3

 `# Python 3 implementation of the approach` `# Function to return the minimum``# operations required``def` `minOperations(n, m):``    ``if` `(m ``%` `n !``=` `0``):``        ``return` `-``1` `    ``minOperations ``=` `0``    ``q ``=` `int``(m ``/` `n)` `    ``# Counting all 2s``    ``while` `(q ``%` `2` `=``=` `0``):``        ``q ``=` `int``(q ``/` `2``)``        ``minOperations ``+``=` `1` `    ``# Counting all 3s``    ``while` `(q ``%` `3` `=``=` `0``):``        ``q ``=` `int``(q ``/` `3``)``        ``minOperations ``+``=` `1` `    ``# If q contained only 2 and 3``    ``# as the only prime factors``    ``# then it must be 1 now``    ``if` `(q ``=``=` `1``):``        ``return` `minOperations` `    ``return` `-``1` `# Driver code``if` `__name__ ``=``=` `'__main__'``:``    ``n ``=` `120``    ``m ``=` `51840``    ``print``(minOperations(n, m))``    ` `# This code is contributed by``# Surendra_Gangwar`

## C#

 `// C# implementation of the approach``using` `System;` `class` `GFG``{` `// Function to return the minimum``// operations required``static` `int` `minOperations(``int` `n, ``int` `m)``{``    ``if` `(m % n != 0)``        ``return` `-1;` `    ``int` `minOperations = 0;``    ``int` `q = m / n;` `    ``// Counting all 2s``    ``while` `(q % 2 == 0)``    ``{``        ``q = q / 2;``        ``minOperations++;``    ``}` `    ``// Counting all 3s``    ``while` `(q % 3 == 0)``    ``{``        ``q = q / 3;``        ``minOperations++;``    ``}` `    ``// If q contained only 2 and 3``    ``// as the only prime factors``    ``// then it must be 1 now``    ``if` `(q == 1)``        ``return` `minOperations;` `    ``return` `-1;``}` `// Driver code``public` `static` `void` `Main()``{``    ``int` `n = 120, m = 51840;``    ``Console.WriteLine(minOperations(n, m));``}``}` `// This code is contributed``// by Akanksha Rai`

## PHP

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## Javascript

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Output:
`7`

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