##### Short Problem Definition:

You are given two strings, A and B. Find if there is a substring that appears in both A and B.

##### Link

##### Complexity:

time complexity is `O(N+M)`

space complexity is `O(1)`

##### Execution:

At first sight this seems like a longest common substring problem. It is actually much easier. You just need to find out if there are two equal *letters* in both strings A and B.

##### Solution:

```
#!/usr/bin/py
def twoStrings(s1, s2):
m1 = set(s1)
m2 = set(s2)
if set.intersection(m1,m2):
return "YES"
return "NO"
if __name__ == '__main__':
t = input()
for _ in xrange(t):
first = raw_input()
second = raw_input()
print twoStrings(first, second)
```