#include <iostream>
using namespace std;
int main(){
    bool ok = true;
    int n;
    cin >> n;
    int a[n + 1];
    a[0] = 0;
    for(int i = 1; i <= n; ++i){
        cin >> a[i];
    }
    for(int i = 1; i <= n; ++i){
        if(a[i - 1] + 1 != a[i]){
            cout << a[i - 1] + 1 << "-" << a[i]-1 << endl;
        }
    }
    if(a[n] != 100){
        cout << a[n] + 1 << "-" << 100 << endl;
    }
    return 0;
}