Q:

Adding and subtract inbetween row inputs and value equal to the first column next row using pandas

Assume I have a dataset with three inputs:
   x1   x2  x3  
0  a    b   c
1  d    e   f
2  g    h   i
3  j    k   l
4  m    n   o
5  p    q   r
6  s    t   u 
      :
      :

0,1,2,3 are times, x1, x2, x3 are inputs that are measured. So here x1 inputs are measured at every one hour. x2 and x3 will be measured at different time. What I need to do , I want write that what ever the measured in x1, x2, x3 it will add and subtract the values are equal to the x1 input next time value 
So here what I want to do is:
    x1   x2   x3   y
 0  a    b    c   a+b-c=d
 1  d    e    f   d+e-f=g
 2  g    h    i   g+h-i=j
 3  j    k    l   j+k-l=m
 4  m    n    o   m+n-o=p
 5  p    q    r   p+q-r=s
 6  s    t    u   s+t-u=v
         :
         :

Here with my actual data according to my csv file:
             X1     x2    x3    y
   0         63      0     0    63+0-0=63
   60(min)   63      0     2    63+0-2 =104
   120       104     11    0    104+11-0=93
   180       93      0    50    93+0-50=177
   240       177     0     2    177+0-2=133
   300       133     0     0    133+0-0=next value of x1

I tried shift method and it didn't work for me what I want exactly. I tried another method and it worked, but didn't came as I want. Here I upload the code.
Code :
 data = pd.read_csv('data6.csv')
 i=0
 j=1
 while j < len(data):
   j=data['x1'][i] - data['x2'][i] + data['x3'][i] 
   i+=1 
   j!=i 
  print(j)

This is works , but it is just showing only one data 

63

In my csv file this is second input value of x1 input.
I want to write this code contonously happened and read the value as I shown above.
Can anyone help me to solve this problem?
My csv file 

A:

I found the answer for this with your help. Thank you very much for helping me. @Adam.Er8 , @U10-Forward and @anky_91
Here is my code:
df = pd.DataFrame(data)     
df['y'] = 0 
for i in range(len(df)-1): #iterating between all the rows of dataframe
   df['y'].iloc[i] == df['x1'].iloc[i] + df['x2'].iloc[i] - df['x3'].iloc[i]
   df['y'].iloc[i] = df['x1'].iloc[i+1]

