Help me in solving RCPITCP13 problem

help
,
1

My issue

not able to solve

My code

#include <stdio.h>

int main() {
    
    // Add the formula for area of 11 and 13
	printf("%d\n",l*b);
	
	// Add the formula for perimeter of 11 and 13
	printf("%d\n",(1/2(l*b))
}

Learning course: Learn C Programming
Problem Link: https://www.codechef.com/learn/course/rcpit-programming-c/RCPITLPC02/problems/RCPITCP13