min4.py

#!/usr/bin/env python
#
# Read line with 4 numbers, and print the minimum

import sys
import string

# Print message to the user
sys.stdout.write("Please enter 4 numbers.\n")

# Read a line from the user
line = sys.stdin.readline()

# Separate the line to strings
ss = string.split(line)

# Check for 4 strings
if len(ss) != 4:
    # Show error message and go away
    sys.stderr.write("Sorry, I did not get 4 numbers\n")
    sys.exit(1)

# Convert the character-strings to integer numbers
w = int(ss[0])
x = int(ss[1])
y = int(ss[2])
z = int(ss[3])

##################################################
#  Now we want to find the minimum of (w,x,y,z) ##
##################################################

# Get min(w,x)
if w < x:
    mwx = w
else:
    mwx = x

# Get min(y,z)
if y < z:
    myz = y
else:
    myz = z

m = mwx;  # Just guess
# But myz may be smaller, so
if myz < m:
    m = myz

# Happy End
sys.stdout.write("... and the minimum is: %d \n" % m)
sys.exit(0)