#Wrote this to entertain myself, on a slow day at work.
#Üstün Ergenoglu

import sys

class Instructions:
    SUBP = 0
    INCP = 1
    DECP = 2
    INCV = 3
    DECV = 4
    OUTPUT = 5
    INPUT = 6
    RET = 7

class BFInterp:
    def __init__(self, text):
        self.programTree = list()
        self.__parse(text)

    def __parse(self, text):
        stack = list()
        stack.append(self.programTree)

        for c in text:
            if c == ">":
                stack[-1].append((Instructions.INCP, 0))
            elif c == "<":
                stack[-1].append((Instructions.DECP, 0))
            elif c == "+":
                stack[-1].append((Instructions.INCV, 0))
            elif c == "-":
                stack[-1].append((Instructions.DECV, 0))
            elif c == ".":
                stack[-1].append((Instructions.OUTPUT, 0))
            elif c == ",":
                stack[-1].append((Instructions.INPUT, 0))
            elif c == "[":
                newList = list()
                stack[-1].append((Instructions.SUBP, newList))
                stack.append(newList)
            elif c == "]":
                stack[-1].append((Instructions.RET, 0))
                stack.pop()

    def run(self):
        self.tape = [0] * (16 * 1024 * 1024)
        self.pointer = 0

        self.__runList(self.programTree)

    def __runList(self, plist):
        pc = 0
        while pc < len(plist):
            i = plist[pc]
            instr = i[0]
            param = i[1]

            if instr == Instructions.INCP:
                self.pointer += 1
            elif instr == Instructions.DECP:
                self.pointer -= 1
            elif instr == Instructions.INCV:
                self.tape[self.pointer] += 1
            elif instr == Instructions.DECV:
                self.tape[self.pointer] -= 1
            elif instr == Instructions.OUTPUT:
                print(chr(self.tape[self.pointer]), end="")
            elif instr == Instructions.INPUT:
                self.tape[self.pointer] = ord(sys.stdin.read(1)[0])
            elif instr == Instructions.SUBP:
                if self.tape[self.pointer] != 0:
                    self.__runList(param)
            elif instr == Instructions.RET:
                if self.tape[self.pointer] != 0:
                    pc = 0
                    continue

            pc += 1

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("usage:", sys.argv[0], "<inputfile>")
        sys.exit(-1)
    sourcefilename = sys.argv[1]
    sourcefile = open(sourcefilename, "rt")
    programText = sourcefile.read()
    sourcefile.close()

    interp = BFInterp(programText)
    interp.run()