659 B | 659 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
BLANK = " "
inp = input
# inp = lambda : sys.stdin.readline()[:-1].strip()
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 solve():
n, m = mii()
price = [ii() for _ in range(n)]
standard = [ii() for _ in range(m)]
cnt = [0] * n
for st in standard:
for i in range(n):
if price[i] <= st:
cnt[i] += 1
break
p(cnt.index(max(cnt)) + 1)
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()