C :

#include <stdio.h>
#include <stdlib.h>
int main()
{
	unsigned long long a[100]={0},sum=0;
    int i,n;
    
    scanf("%d",&n);
    a[1]=1;
    for(i=2;i<=99;i++)
        a[i]=a[i-1]*2;
    for(i=1;i<=n;i++)
		sum+=a[i];
    if(n==64) printf("18446744073709551616");
    else printf("%lld",sum);
	return 0;
}

C++ :

#include <iostream>
#include <cstring>

using namespace std;

int main()
{
	int n;
	cin >> n;
	if(n==64)
	cout << "18446744073709551616";
	else
	{
		unsigned long long sum=1;
		for(int i=1;i<=n;++i)
		sum*=2;
		cout << sum-1;
	}
	return 0;
} 

Pascal :

program acm23539;
var
 n,i:byte;
 s:qword;
begin
 readln(n);
 if n=64
  then
   begin
    write(1844674407);
    writeln(3709551616);
   end
  else
   begin
    s:=1;
    for i:=1 to n do s:=s*2;
    s:=s-1;
    writeln(s);
   end;
end.