Basic if statement: 

if _______:
  something

The program becomes two dimensional.

Note: something is a block of statements, indentation is necessary.

Complete if statement template: 

if _______:
  something
else:
  something_else

This sums up both templates when we say the else is optional. 

Both branches contain blocks of statements. 

We developed a simple program:

n = int(raw_input("First number: "))
m = int(raw_input("Second number: "))

if n >= m: 
  print n
else:
  print m

print max(m, n)

print (n + m + abs(n-m)) / 2

Note that (n + m) / 2 + abs(n - m) / 2 is incorrect in half the cases. 

Finally we worked this out: 

timeOne = raw_input("Enter first time: ")
timeTwo = raw_input("Enter second time: ")

t1 = int(timeOne[0:2]) * 60 + int(timeOne[2:])
t2 = int(timeTwo[0:2]) * 60 + int(timeTwo[2:])

if (t2 >= t1):
    pass
else:
    t2 = t2 + 24 * 60

d = t2 - t1 
print d / 60, "hours and", d % 60

In the process we also reviewed what we knew about strings:

a) they're sequences of chars in between delimiters (" or ')
b) they're immutable
c) len(...) knows how to calculate their length
d) chars inside are indexed left to right starting from 0
e) we can slice strings with [n:m] or [n:] 
f) chars are indexed right to left starting with -1

In lab we're going to work on the posted problems.