Help me in solving SESO42 problem

My issue

sol.cpp:47:5: error: redefinition of ‘int main()’
47 | int main() {
| ^~~~
sol.cpp:21:5: note: ‘int main()’ previously defined here
21 | int main() {
| ^~~~

My code

void insertionSort(int arr[], int n) {
    // Write your code here
}

Learning course: Data structures & Algorithms lab
Problem Link: https://www.codechef.com/learn/course/muj-aiml-dsa-c/MUJADSAC15/problems/SESO42