#include "stdio.h"

int main(){
    int n, n_i, n_ii;
    int start = 0;
    int stop = 0;
    // il citesc pe n
    scanf("%d", &n);
    // citesc numerele si calculez intervalele care nu le am
    for (size_t i = 0; i < n; i++) {
        scanf("%d", &n_i);
        if ((n_i > stop) && (n_i-1 != n_ii)) {
            stop = n_i - 1;
            printf("%d-%d\n",start, stop);
            start = n_i + 1;
            n_ii = n_i;
        }
    }
    if (n_i < 100) {
        printf("%d-%d\n",start, 100);
    }
    return 0;
}