高精度的！！！

#include
using namespace std;
int a[10000];

int zf(int n) {
	a[0] = 1;
	for (int j = 0; j < n; j++) {
		int x = 0;
		for (int i = 0; i < 2000; i++) {
			a[i] = a[i] * 2 + x;
			x = a[i] / 10;
			a[i] = a[i] % 10;
		}
	}
	int x = 0;
	for (int i = 0; i < 2000; i++) {
		if (a[i] == 0 && a[i - 1] == 0 && a[i - 2] == 0) {
			x = i;
			break;
		}
	}
	x -= 3;
	a[0]--;
	for (int i = x; i >= 0; i--) {
		cout << a[i];
	}
	return 1;
}

int main() {
	int n;
	cin >> n;
	zf(n);
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
int a[10000];

int zf(int n) {
	a[0] = 1;
	for (int j = 0; j < n; j++) {
		int x = 0;
		for (int i = 0; i < 2000; i++) {
			a[i] = a[i] * 2 + x;
			x = a[i] / 10;
			a[i] = a[i] % 10;
		}
	}
	int x = 0;
	for (int i = 0; i < 2000; i++) {
		if (a[i] == 0 && a[i - 1] == 0 && a[i - 2] == 0) {
			x = i;
			break;
		}
	}
	x -= 3;
	a[0]--;
	for (int i = x; i >= 0; i--) {
		cout << a[i];
	}
	return 1;
}

int main() {
	int n;
	cin >> n;
	zf(n);
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
long long a[101],n;
int main(){
	cin>>n;
	a[1]=1;
	a[2]=3;
	for(int i=1;i<=n;i++)
	a[i]=a[i-1]*2+1;
	cout<<a[n];
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
long long s=1;
long long n;
int main(){
	cin>>n;
	for(int i=1;i<n;i++){
		s=s*2+1;
	}
	cout<<s;
}
///
///    	   __  __          __  
/// 	  / / / /_  ______/ /________ 
///      / /_/ / / / / __  / ___/ __ \
/// 	/ __  / /_/ / /_/ / /  / /_/ /
///    /_/ /_/\__, /\__,_/_/   \____/ 
///          /____/                   
///