# Python: Find the number of combinations of a,b,c and d

## Python Basic - 1: Exercise-37 with Solution

Write a Python program that reads an integer n and finds the number of combinations of a,b,c and d (0 = a,b,c,d = 9) where (a + b + c + d) will be equal to n.

**Input:**

n (1 ≤ n ≤ 50)

Input the number(n): 15

Number of combinations: 592

**Sample Solution**:

**Python Code:**

```
# Import the itertools module to work with iterators and combinatorial functions
import itertools
# Prompt the user to input a number 'n'
print("Input the number(n):")
# Read the user input and convert it to an integer
n = int(input())
# Initialize the variable 'result' to store the count of combinations
result = 0
# Iterate over all combinations of (i, j, k) where i, j, k are in the range [0, 9]
for (i, j, k) in itertools.product(range(10), range(10), range(10)):
# Check if the sum of i, j, and k lies between 0 and 9 (inclusive)
result += (0 <= n - (i + j + k) <= 9)
# Print the number of combinations that satisfy the condition
print("Number of combinations:", result)
```

Sample Output:

Input the number(n): 15 Number of combinations: 592

**Explanation: **

The above Python code prompts the user to input a number 'n' and then counts the number of combinations of three digits (i, j, k), where each digit ranges from 0 to 9, such that their sum is equal to 'n'. The code utilizes the itertools module to generate all possible combinations of (i, j, k) and increments a counter 'result' whenever the sum of these digits falls between 0 and 9 (inclusive).

Finally, it prints the count of combinations that satisfy the given condition.

**Flowchart:**

**Python Code Editor:**

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