def continuous_frost(n, temperature_ranges):
    longest_frost = 0
    current_frost = 0
    start_day = -1
    best_start_day = -1

    for i in range(n):
        min_temp, max_temp = temperature_ranges[i]

        if max_temp < 0:  # Continuous frost condition
            if current_frost == 0:
                start_day = i + 1
            current_frost += 1
        else:
            if current_frost > longest_frost:
                longest_frost = current_frost
                best_start_day = start_day
            current_frost = 0

    if current_frost > longest_frost:
        longest_frost = current_frost
        best_start_day = start_day

    if longest_frost == 0:
        return -1
    else:
        return best_start_day

n = 5
temperature_ranges = [(-5, 2), (-6, -4), (-3, -2), (-8, -5), (-2, 1)]

result = continuous_frost(n, temperature_ranges)
print(result)