def parse(inFile):
    inFile.getInt()
    return inFile.getInts()

def solve(data):
    print data
    return "%.6f" % len([k for k in xrange(len(data)) if data[k] != k + 1])

if __name__ == "__main__":
    from GCJ import GCJ
    GCJ(parse, solve, "/Users/lpebody/gcj/2011_q/", "d").run()