A = list(map(int, input().split()))
B = list(map(int, input().split()))
C, D = map(int, input().split())

a = max(0, C-A[1])
b = min(C, A[1])
B[0] += a
B[1] += b

A[0] -= a

A[0] += min(D, B[0])

print(A[0])