One possibility is to loop over an index to both strings:

```
s1, s2 = 'noiseless', 'nuisances'
h = 0
for i in range(len(s1)):
if s1[i] != s2[i]:
h += 1
print('The Hamming distance between the strings "{:s}" and "{:s}" is {:d}.'
.format(s1, s2, h))
```

However, since we need to loop over two sequences at the same time, the more Pythonic solution is to zip them:

```
s1, s2 = 'noiseless', 'nuisances'
h = 0
for c1, c2 in zip(s1, s2):
if c1 != c2:
h += 1
print('The Hamming distance between the strings "{:s}" and "{:s}" is {:d}.'
.format(s1, s2, h))
```

`zip(s1,s2)`

produces the sequence of character pairs taken from the strings: `('n', 'n')`

, `('o', 'u')`

, ...