0分求条，玄关

#include <bits/stdc++.h>
#define int long long
//unsigned long long
using namespace std;
const int N=1e6+50;
int a[N];
int n;
bool p=1;
int k=0;
bool f[N];

signed main() {
	freopen("game.in","r",stdin);
	freopen("game.out","w",stdout);
    cin>>n;
    for(int i=0;i<n;i++){
    	cin>>a[i];
    	if(f[a[i]]==0){
    		f[a[i]]=1;
    		k++;
		}
	}
	if(k!=1){
		p=0;
	}
	if(p==1){
		cout<<"1:0";
	}
	else{
		int kkkk=0,mii=-1;
		for(int i=0;i<n;i++){
			if(f[i]==1){
				if(kkkk==0)kkkk=1;
				else mii=i;break; 
			}
		}
		int u=min(n-mii-1,mii+1);
		if(u%2==1){
			cout<<"2:0";
		}
		else{
			cout<<"1:1";
		}
	}
	return 0;
}