You are given two strings $S$ and $R$. Each of these strings has length $N$. We want to make $S$ equal to $R$ by performing the following operation some number of times (possibly zero):
- Choose two integers $a$ and $b$ such that $1 \le a \le b \le N$.
- For each $i$ such that $a \le i \le b$, replace the $i$-th character of $S$ by the $i$-th character of $R$.
Suppose that we make $S$ equal to $R$ by performing this operation $k$ times, in such a way that the total number of replaced characters (i.e. the sum of all $k$ values of $b-a+1$) is $l$. Then, the cost of this process is defined as $k \cdot l$.
Find the minimum cost with which we can make $S$ equal to $R$.

-----Input-----
- The first line of the input contains a single integer $T$ denoting the number of test cases. The description of $T$ test cases follows.
- The first line of each test case contains a single string $S$.
- The second line contains a single string $R$.

-----Output-----
For each test case, print a single line containing one integer ― the minimum cost.

-----Constraints-----
- $1 \le T \le 4,000$
- $1 \le N \le 10^6$
- $|S| = |R| = N$
- $S$ and $R$ contain only lowercase English letters
- the sum of $N$ over all test cases does not exceed $2 \cdot 10^6$

-----Example Input-----
1
adefb
bdefa

-----Example Output-----
4

-----Explanation-----
Example case 1: $S$ can be made equal to $R$ in two moves. First, we replace $S_1$ by $R_1$ and then replace $S_5$ by $R_5$. We have $k = l = 2$, so the cost is $2 \cdot 2 = 4$. If we wanted to perform only one operation, the cost would be $5$.

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

ns = {"__name__": "__main__"}
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = 't=int(input())\nfor _ in range(t):\n s=input()\n r=input()\n ans=1000000000000000\n c=0\n l=0\n k=0\n for i in range(len(s)):\n  if s[i]!=r[i]:\n   c+=1\n   l+=1\n   if c==1:\n    k+=1\n  else:\n   c=0\n a=0\n b=0\n ans=k*l\n for i in range(len(s)-1,-1,-1):\n  if s[i]!=r[i]:\n   b=i\n   break\n for i in range(len(s)):\n  if s[i]!=r[i]:\n   a=i\n   break\n gap=[];c=0\n for i in range(a,b+1):\n  if s[i]==r[i]:\n   c+=1\n  else:\n   if c!=0:\n    gap.append(c)\n    c=0\n #print(gap,k,l)\n gap.sort()\n for i in gap:\n  k-=1\n  l+=i\n  ans=min(ans,k*l)\n print(ans)\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: 13467