# USACO Bronze division

# Measuring Traffic

The highway adjacent to Farmer John's farm has recently seen a dramatic increase in traffic, or at least so it seems to Farmer John. To be sure, he wants to measure the traffic flow on the highway with a set of sensors, each capable of measuring the rate of flow of traffic on a segment of road.

Unfortunately, while walking through the barn one day, Farmer John trips and drops his box of sensors into a large vat of milk, after which they no longer work as well. Instead of producing a single exact reading of traffic flow rate, each sensor now outputs a range of possible values. For example, a sensor might output the range [**7**, **13**], indicating that the rate of traffic flow on a segment of road is no less than **7**, and no greater than **13**.

The highway runs for **n** miles next to the farm, and traffic on the highway only flows in one direction, from mile **1** towards mile **n**. Farmer John wants to install **n** sensors - one for each **1**-mile segment of the highway. In some of these segments, there are on-ramps that allow traffic to enter the highway; in each of these cases, Farmer John will install his sensor on the on-ramp to measure (approximately) the amount of incoming traffic. In some segments there are off-ramps that allows traffic to exit the highway; in each of these cases, Farmer John will install his sensor on the off-ramp. Each segment contains at most one ramp. If there is no on-ramp or off-ramp in a segment of highway, Farmer John installs a sensor on the main highway itself.

Given the readings from Farmer John's **n** sensors, please determine the most specific possible ranges that describe the rate of traffic flow initially on the highway prior to mile **1** and for traffic continuing on the highway past mile **n**. These ranges should be consistent with all **n** sensor readings.

#### Input

The first line contains number **n** (**1** ≤ **n** ≤ **100**). Each of the remaining **n** lines describes a **1**-mile segment of the road, in order from mile **1** to mile **n**. Each line contains a string that is either **"on"** (if there is an on-ramp on this segment), **"off"** (if there is an off-ramp), or **"none"** (if there is no ramp), followed by two integers in the range **0**..**1000**, indicating the lower and upper endpoints of the sensor range from this segment. If the segment contains a ramp, the sensor reading is from the ramp. Otherwise, it is from the main highway. At least one of the highway segments will be designated as **"none"**.

#### Output

The first line should contain two integers giving the most specific range possible for the rate of traffic flow prior to mile **1**. The second line of output should contain two integers giving the most specific range possible for the rate of traffic flow after mile **n**. A valid solution is always guaranteed to exist.

#### Example

The combination of readings from segments **2** and **3** tell us that the flow rate through these segments is somewhere in the range [**11**, **14**], since only this range is consistent with both the readings [**10**, **14**] and [**11**, **15**]. In mile **1**, exactly **1** unit of flow enters on an on-ramp, so prior to mile **1**, the flow rate must be in the range [**10**, **13**]. In mile **4**, between **2** and **3** units exits on an off-ramp, so the range of possible flow rates after this is [**8**, **12**].

4 on 1 1 none 10 14 none 11 15 off 2 3

10 13 8 12