View Code of Problem 73

#include<stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
    int n,sum=1;
    scanf("%d",&n);
    while(n>1){
        sum+=1;
        sum*=2;
        n--;
    }
    printf("%d\n",sum);
	return 0;
}