def find_common_characters(msg1,msg2):
    l=[]
    for i in msg1:
        if((i in msg2) and i!=' '):
            l.append(i)
    a = "".join(l)
    if(a):
        return a
    else:
        return -1
msg1="I like Python"
msg2="Java is a very popular language"
common_characters=find_common_characters(msg1,msg2)
print(common_characters)