#include <bits/stdc++.h>

using namespace std;

int n,v[100],k,c[100],ok=1,pos;

int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
        {cin>>v[i];
        c[v[i]]=v[i];}
    for(int i=1;i<=100;i++)
    {
        if(i != c[i])
        {
            ok==0;
            pos=i;
            while(c[i] != i && i<=100){
                i++;
            }
            cout<<pos<<"-"<<i-1<<'\n';
        }
    }

    return 0;
}