788 B | 788 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
# sys.setrecursionlimit(10**7)
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline().rstrip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def gcd(a, b): return gcd(b, a % b) if b > 0 else a
def lcm(a, b): return a * b // gcd(a, b)
def solve():
k, w = mii()
l = [inp() for _ in range(w)]
ans = l[0]
for i in range(1, w):
crt = l[i]
for j in range(k, 0, -1):
if ans[-j:] == crt[:j]:
ans += crt[j:]
break
else:
ans += crt
p(len(ans))
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
ret = solve()