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ManycontainersaretransportedbyshipstotheJOIPorteveryday. Theyaretransportedtoalloverthecountry by trucks. The JOI Port is very narrow. It has only two areas where we can put containers. In each area, we can put any number of containers vertically. For safety reasons, when a container is transported by a ship, we have to put it on one of the areas. If some containers are already put there, we have to put it on the top of them. When we transport a container by a truck, we have to take a container from the top of the containers on one of the areas. Today, N containers will be transported to the JOI Port. All of them will be transported by trucks. Your task is to manage the facilities of the JOI Port. For each container, you know when it will come and when it will leave. Write a program which calculates the number of ways to put and take containers modulo 1000000007.