def boardCutting(cost_y, cost_x):
    cost = 0
    seg = [1,1]
    y = sorted(cost_y,reverse=True)
    x = sorted(cost_x,reverse=True)
    for a in range(len(x)+len(y)):
        if len(x) is 0:
            cost+=(seg[0]*y[0])%(10**9+7)
            y.pop(0)
            seg[1]+=1
        elif len(y) is 0:
            cost+=(seg[1]*x[0])%(10**9+7)
            x.pop(0)
            seg[0]+=1
        else:    
            if x[0]>y[0]:
                cost+=(seg[1]*x[0])%(10**9+7)
                x.pop(0)
                seg[0]+=1
            elif y[0]>x[0]:
                cost+=(seg[0]*y[0])%(10**9+7)
                y.pop(0)
                seg[1]+=1
            else:
                if seg[1]>seg[0]:
                    cost+=(seg[0]*y[0])%(10**9+7)
                    y.pop(0)
                    seg[1]+=1
                else:
                    cost+=(seg[1]*x[0])%(10**9+7)
                    x.pop(0)
                    seg[0]+=1

    return int(cost%(10**9+7))