1 2 3 4 -> 1 
1 2 3 5 -> 1 
1 2 3 6 -> 1 
1 2 3 7 -> 7 
1 2 4 5 -> 1 
1 2 4 6 -> 1 
1 2 4 7 -> 7 
1 2 5 6 -> 5 
1 2 5 7 -> 7 
1 2 6 7 -> 6 
1 3 4 5 -> 3 
1 3 4 6 -> 3 
1 3 4 7 -> 7 
1 3 5 6 -> 5 
1 3 5 7 -> 7 
1 3 6 7 -> 6 
1 4 5 6 -> 4 
1 4 5 7 -> 4 
1 4 6 7 -> 6 
1 5 6 7 -> 5 
2 3 4 5 -> 2 
2 3 4 6 -> 2 
2 3 4 7 -> 2 
2 3 5 6 -> 2 
2 3 5 7 -> 2 
2 3 6 7 -> 6 
2 4 5 6 -> 4 
2 4 5 7 -> 4 
2 4 6 7 -> 6 
2 5 6 7 -> 5 
3 4 5 6 -> 3 
3 4 5 7 -> 3 
3 4 6 7 -> 3 
3 5 6 7 -> 5 
4 5 6 7 -> 4