for name in ['Newton', 'x', 'Euler']:
    if 'x' in name:
        continue
    else:
        print(name[0])

for name in []:
    print("Names were given.")
else:
    print("No names were given.")

for name in ['Hilbert', 'Mark', 'Hardy']:
    if name == 'Mark':
        print("Mark is the greatest!")
        break
    else:
        print(name[0])