#include	<vector>
#include	<iostream>
#include	<fstream>
#include	<algorithm>

using namespace std;

int a[101] ;

int main(){
//    freopen("a.in","r",stdin) ;


    int n ;
    cin >> n ;
    int x ;

    while ( n -- ){
        cin >> x ;
        ++a[x] ;
    }

    for (int i = 1 ; i <= 100 ; ++i){
            if(a[i] == 0){
                    cout << i << '-' ;
                    int k ;
                    for(k = i+1 ; a[k] == 0 && k <= 100 ; ++k);
                    if (k == i+1){
                        cout << k -1  << '\n' ;
                    }else{
                        i = k ;
                        cout << i << '\n' ;

                    }

            }
    }



return (0);
}