#include <stdio.h>

int main() {
    int AW, AB, BW, BB,C,D;

    scanf("%d %d", &AW, &AB);
    scanf("%d %d", &BW, &BB);
    scanf("%d %d", &C, &D);

    //移動数>A黒
    if (C > AB) {
        BW += (C - AB);
        AW -= (C - AB);
    }
    //移動数<B白
    if (D < BW) AW += D;
    else AW += BW;

    printf("%d\n", AW);
    return 0;

}