View Code of Problem 73

#include "stdio.h"
#include "math.h"
#include "string.h"

void  main()
{
	int n,i;
	int sum=1;
	scanf("%d",&n);
	for(i=0;i<n-1;i++)
	{
		sum=(sum+1)*2;
	}
	printf("%d",sum);
}