import sys
import re


def past_verb(s):
#    print(s[-1])
    if s[-1]  ==  "y":
        return s + "ed"
    elif s[-1] =="ry":
        return s[:-2] + "ied"
    elif s[-1] == "e":
        return s  + "d"
    elif s[-1] == "p":
        return s + "ped"
    elif s[-1] == "c":
        return s + "ked"
    elif s[-1] == "o":
        return s + "ne"
    elif s == "put":
        return s
    else:
        return s + "ed"
if __name__ == '__main__':
    print(past_verb("play"))
    print(past_verb("try"))
    print(past_verb("like"))
    print(past_verb("stop"))
    print(past_verb("picnic"))
    print(past_verb("go"))
    print(past_verb("put"))