python中的缩进问题

#!/usr/bin/python 
l=0
for i in range(1,5):
    for j in range(1,5):
        for k in range(1,5):
            if( i != k ) and (i != j) and (j != k):
                print(i,j,k)

                l+=1

                print(l)

出错：i+=1        ^ TabError: inconsistent use of tabs and spaces in indentation  exit status 1===>看不出来换到同一行上

#!/usr/bin/python 
l=0
for i in range(1,5):
    for j in range(1,5):
        for k in range(1,5):
            if( i != k ) and (i != j) and (j != k):
                print(i,j,k);l+=1;print(l)

运行结果：正确

1 2 3
1
1 2 4
2
1 3 2
3
1 3 4
4
1 4 2
5
1 4 3
6