# coding: utf-8
def get_ln_inputs():
    return input().split()


def get_ln_int_inputs():
    return list(map(int, get_ln_inputs()))


def main():
    print(get_ln_inputs()[0][::2])


main()
ac00ac128be5a213da97c9b4b8f56a0b1bae46d1
<mask token>


def get_ln_int_inputs():
    return list(map(int, get_ln_inputs()))


<mask token>

def get_ln_inputs():
    return input().split()


def get_ln_int_inputs():
    return list(map(int, get_ln_inputs()))


<mask token>

def get_ln_inputs():
    return input().split()


def get_ln_int_inputs():
    return list(map(int, get_ln_inputs()))


def main():
    print(get_ln_inputs()[0][::2])


<mask token>

def get_ln_inputs():
    return input().split()


def get_ln_int_inputs():
    return list(map(int, get_ln_inputs()))


def main():
    print(get_ln_inputs()[0][::2])


main()

# coding: utf-8
def get_ln_inputs():
    return input().split()


def get_ln_int_inputs():
    return list(map(int, get_ln_inputs()))


def main():
    print(get_ln_inputs()[0][::2])


main()