def intersperse():
    print('Please input 2 strings that are the same length.')
    string1 = '123'
    string2 = '45'
    while(len(string1) != len(string2)):
        string1 = input('string1: ')
        string2 = input('string2: ')
    output_string = ''
    for num in range(len(string1)):
        output_string=output_string+string1[num]+string2[num]
    return(output_string)