#!/usr/bin/env python3
A, B = map(int, input().split())
a = list(map(int, input().split()))
b = list(map(int, input().split()))
dp = [[0] * (B + 1) for _ in range(A + 1)]

for i in range(A)[::-1]:
    dp[i][B] = dp[i + 1][B] + a[i] if (i + B) % 2 == 0 else dp[i + 1][B]
for j in range(B)[::-1]:
    dp[A][j] = dp[A][j + 1] + b[j] if (A + j) % 2 == 0 else dp[A][j + 1]

for i in range(A)[::-1]:
    for j in range(B)[::-1]:
        dp[i][j] = \
        max(dp[i + 1][j] + a[i], dp[i][j + 1] + b[j]) if (i + j) % 2 == 0 else \
        min(dp[i + 1][j], dp[i][j + 1])

print(dp[0][0])
