WA #8 ，#9，#10

#include<bits/stdc++.h>
using namespace std;
int arr[60];
int cc=1;
int main(){
	__int128 a=1;
	__int128 b=0;
	int n;
	cin>>n;
	for(int i=1;i<=n;i++){
		b*=2;
		a*=2;
		b+=a/100000000000000000000000000000000;
		a%=100000000000000000000000000000000;
	}
	a--;
	b*=2;
	a*=2;
	b+=a/100000000000000000000000000000000;
	a%=100000000000000000000000000000000;
	for(int i=1;i<=30;i++){
		if(a==0){
			break;
		}
		arr[cc]=a%10;
		a/=10;cc++;
	}
	for(int i=1;i<=30;i++){
		if(b==0){
			break;
		}
		arr[cc]=b%10;
		b/=10;cc++;
	}
	for(int i=cc;i>=1;i--){
		if(i==cc&&arr[cc]==0){
			i--;
		}
		cout<<arr[i];
	}
	return 0;
}