r,c,x1,y1,x2,y2=map(int,input().split())
M=[list(input()) for i in range(r)]
ans=""
if x1==x2:
    for k in range(y1,y2+1):
        ans+=M[x1-1][k-1]
elif y1==y2:
    for k in range(x1,x2+1):
        ans+=M[k-1][y1-1]
else:
    for k in range(0,x2-x1+1):
        ans+=M[x1+k-1][y1+k-1]
print(ans)