#include <iostream>
#include <fstream>

using namespace std;

ifstream fin("elmaj.in");
ofstream fout("elmaj.out");


int sir[1000000];

int main(){
    int n, i, fr = 0, numar;
    fin >> n;
    for(i = 0;i < n;i++){
        fin >> sir[i];
    }
    for(i = 0; i < n; i++){
        if(sir[i] == sir [i + 1]){
            fr++;
            numar = sir[i];
        }else if(sir[i] != sir[i + 1] && (sir[i] == numar || sir[i + 1] == numar)){
            fr--;
        }
    }
    if(fr > 0){
        cout << numar;
    } else {
        cout << "nu";
    }
    return 0;
}