0
1
2
1
x1
1
2
1
1
0
1
2
0
1
2
x1
0
1
2
1
x1
1
2
1
1
0
1
2
0
1
2
0
1
2
x1
0
1
2
1
x1
1
2
1
1
0
1
2
0
1
2
0
1
2
0
1
2
x1
0
1
2
1
x1
1
2
1
1
0
1
2
0
1
2
0
1
2
0
1
2
0
1
2
x1
0
1
2
1
x1
1
2
1
1
0
1
2
0
1
2
0
1
2
0
1
2
0
1
2
0
1
2
x1
0
1
1
1
2
1
FULL
TRS//ICFP_2010/26103.srs