#include <iostream>

int main() {
    unsigned int count, actual, previous;
    std::cin >> count >> actual;
    if(actual - 1 > 0)
        std::cout << 1 << '-' << actual - 1 << std::endl;
    previous = actual;
    for(size_t it = 2; it <= count; it++) {
        std::cin >> actual;

        if(actual - previous > 1)
            std::cout << previous + 1 << '-' << actual - 1 << std::endl;

        previous = actual;
    }

    if(100 - previous > 0)
        std::cout << previous + 1 << '-' << 100;
    return 0;
}