Help me in solving LPYAS155 problem

[kl_2300033816]

My issue

how to solve

My code

#include <stdio.h>

int main() {
    int num,sum=0;
    scanf("%d",&num);
}

Learning course: Roadmap to 3*
Problem Link: https://www.codechef.com/learn/course/klu-roadmap-3star/KLURMP300B/problems/LPYAS155