Pdb Crashed: Cannot Set Breakpoint

I suddenly cannot set any breakpoint in my python program. Note there are two (Pdb) showing up. I wonder if the Pdb was damaged before. I did try to step into some compiled C++ cod

Solution 1:

Now I figured it out that the Pdb is not malfunctioning. It is because Python reads from stdin right next to the Pdb, which enters to the Pdb's interactive console and causing a problem. So a bypass is to read from file instead of stdin

fp = open(sys.argv[1], 'r')  
t = int(fp.readline())

instead of

t = int(raw_input())