#!/usr/bin/env python
#coding:utf8


def read():
    Aw, Ab = map(int, raw_input().split())
    Bw, Bb = map(int, raw_input().split())
    C, D   = map(int, raw_input().split())
    return Aw, Ab, Bw, Bb, C, D
    

def work((Aw, Ab, Bw, Bb, C, D)):
    moveAb = min(Ab, C)
    moveAw = min(Aw, C - moveAb)

    Ab -= moveAb
    Aw -= moveAw
    Bb += moveAb
    Bw += moveAw

    moveBw = min(Bw, D)
    moveBb = min(Bb, D - moveBw)

    Bw -= moveBw
    Bb -= moveBb
    Aw += moveBw
    Ab += moveBb

    print Aw


if __name__ == "__main__":
    work(read())