c pigeon-9: placing 10 pigeons into 9 holes
c 
c File generated by 'pigeonhole', (c) Tjark Weber
c 
c The SAT encoding of this problem is very straightforward.  For each pigeon i
c and each hole j we have a variable x_{n*(i-1)+j} which means that pigeon i
c is placed in hole j.  Then we have n+1 clauses which say that a pigeon has
c to be placed in some hole.  Then for each hole we have a set of clauses
c ensuring that only one single pigeon is placed into that hole.
c 
c This encoding leads to a total of (n+1) * n propositional variables and
c (n+1) + n * (n * (n+1) / 2) clauses.
c 
c The resulting SAT problem is unsatisfiable.
c 
p cnf 90 415
1 2 3 4 5 6 7 8 9 0
10 11 12 13 14 15 16 17 18 0
19 20 21 22 23 24 25 26 27 0
28 29 30 31 32 33 34 35 36 0
37 38 39 40 41 42 43 44 45 0
46 47 48 49 50 51 52 53 54 0
55 56 57 58 59 60 61 62 63 0
64 65 66 67 68 69 70 71 72 0
73 74 75 76 77 78 79 80 81 0
82 83 84 85 86 87 88 89 90 0
-1 -10 0
-1 -19 0
-1 -28 0
-1 -37 0
-1 -46 0
-1 -55 0
-1 -64 0
-1 -73 0
-1 -82 0
-10 -19 0
-10 -28 0
-10 -37 0
-10 -46 0
-10 -55 0
-10 -64 0
-10 -73 0
-10 -82 0
-19 -28 0
-19 -37 0
-19 -46 0
-19 -55 0
-19 -64 0
-19 -73 0
-19 -82 0
-28 -37 0
-28 -46 0
-28 -55 0
-28 -64 0
-28 -73 0
-28 -82 0
-37 -46 0
-37 -55 0
-37 -64 0
-37 -73 0
-37 -82 0
-46 -55 0
-46 -64 0
-46 -73 0
-46 -82 0
-55 -64 0
-55 -73 0
-55 -82 0
-64 -73 0
-64 -82 0
-73 -82 0
-2 -11 0
-2 -20 0
-2 -29 0
-2 -38 0
-2 -47 0
-2 -56 0
-2 -65 0
-2 -74 0
-2 -83 0
-11 -20 0
-11 -29 0
-11 -38 0
-11 -47 0
-11 -56 0
-11 -65 0
-11 -74 0
-11 -83 0
-20 -29 0
-20 -38 0
-20 -47 0
-20 -56 0
-20 -65 0
-20 -74 0
-20 -83 0
-29 -38 0
-29 -47 0
-29 -56 0
-29 -65 0
-29 -74 0
-29 -83 0
-38 -47 0
-38 -56 0
-38 -65 0
-38 -74 0
-38 -83 0
-47 -56 0
-47 -65 0
-47 -74 0
-47 -83 0
-56 -65 0
-56 -74 0
-56 -83 0
-65 -74 0
-65 -83 0
-74 -83 0
-3 -12 0
-3 -21 0
-3 -30 0
-3 -39 0
-3 -48 0
-3 -57 0
-3 -66 0
-3 -75 0
-3 -84 0
-12 -21 0
-12 -30 0
-12 -39 0
-12 -48 0
-12 -57 0
-12 -66 0
-12 -75 0
-12 -84 0
-21 -30 0
-21 -39 0
-21 -48 0
-21 -57 0
-21 -66 0
-21 -75 0
-21 -84 0
-30 -39 0
-30 -48 0
-30 -57 0
-30 -66 0
-30 -75 0
-30 -84 0
-39 -48 0
-39 -57 0
-39 -66 0
-39 -75 0
-39 -84 0
-48 -57 0
-48 -66 0
-48 -75 0
-48 -84 0
-57 -66 0
-57 -75 0
-57 -84 0
-66 -75 0
-66 -84 0
-75 -84 0
-4 -13 0
-4 -22 0
-4 -31 0
-4 -40 0
-4 -49 0
-4 -58 0
-4 -67 0
-4 -76 0
-4 -85 0
-13 -22 0
-13 -31 0
-13 -40 0
-13 -49 0
-13 -58 0
-13 -67 0
-13 -76 0
-13 -85 0
-22 -31 0
-22 -40 0
-22 -49 0
-22 -58 0
-22 -67 0
-22 -76 0
-22 -85 0
-31 -40 0
-31 -49 0
-31 -58 0
-31 -67 0
-31 -76 0
-31 -85 0
-40 -49 0
-40 -58 0
-40 -67 0
-40 -76 0
-40 -85 0
-49 -58 0
-49 -67 0
-49 -76 0
-49 -85 0
-58 -67 0
-58 -76 0
-58 -85 0
-67 -76 0
-67 -85 0
-76 -85 0
-5 -14 0
-5 -23 0
-5 -32 0
-5 -41 0
-5 -50 0
-5 -59 0
-5 -68 0
-5 -77 0
-5 -86 0
-14 -23 0
-14 -32 0
-14 -41 0
-14 -50 0
-14 -59 0
-14 -68 0
-14 -77 0
-14 -86 0
-23 -32 0
-23 -41 0
-23 -50 0
-23 -59 0
-23 -68 0
-23 -77 0
-23 -86 0
-32 -41 0
-32 -50 0
-32 -59 0
-32 -68 0
-32 -77 0
-32 -86 0
-41 -50 0
-41 -59 0
-41 -68 0
-41 -77 0
-41 -86 0
-50 -59 0
-50 -68 0
-50 -77 0
-50 -86 0
-59 -68 0
-59 -77 0
-59 -86 0
-68 -77 0
-68 -86 0
-77 -86 0
-6 -15 0
-6 -24 0
-6 -33 0
-6 -42 0
-6 -51 0
-6 -60 0
-6 -69 0
-6 -78 0
-6 -87 0
-15 -24 0
-15 -33 0
-15 -42 0
-15 -51 0
-15 -60 0
-15 -69 0
-15 -78 0
-15 -87 0
-24 -33 0
-24 -42 0
-24 -51 0
-24 -60 0
-24 -69 0
-24 -78 0
-24 -87 0
-33 -42 0
-33 -51 0
-33 -60 0
-33 -69 0
-33 -78 0
-33 -87 0
-42 -51 0
-42 -60 0
-42 -69 0
-42 -78 0
-42 -87 0
-51 -60 0
-51 -69 0
-51 -78 0
-51 -87 0
-60 -69 0
-60 -78 0
-60 -87 0
-69 -78 0
-69 -87 0
-78 -87 0
-7 -16 0
-7 -25 0
-7 -34 0
-7 -43 0
-7 -52 0
-7 -61 0
-7 -70 0
-7 -79 0
-7 -88 0
-16 -25 0
-16 -34 0
-16 -43 0
-16 -52 0
-16 -61 0
-16 -70 0
-16 -79 0
-16 -88 0
-25 -34 0
-25 -43 0
-25 -52 0
-25 -61 0
-25 -70 0
-25 -79 0
-25 -88 0
-34 -43 0
-34 -52 0
-34 -61 0
-34 -70 0
-34 -79 0
-34 -88 0
-43 -52 0
-43 -61 0
-43 -70 0
-43 -79 0
-43 -88 0
-52 -61 0
-52 -70 0
-52 -79 0
-52 -88 0
-61 -70 0
-61 -79 0
-61 -88 0
-70 -79 0
-70 -88 0
-79 -88 0
-8 -17 0
-8 -26 0
-8 -35 0
-8 -44 0
-8 -53 0
-8 -62 0
-8 -71 0
-8 -80 0
-8 -89 0
-17 -26 0
-17 -35 0
-17 -44 0
-17 -53 0
-17 -62 0
-17 -71 0
-17 -80 0
-17 -89 0
-26 -35 0
-26 -44 0
-26 -53 0
-26 -62 0
-26 -71 0
-26 -80 0
-26 -89 0
-35 -44 0
-35 -53 0
-35 -62 0
-35 -71 0
-35 -80 0
-35 -89 0
-44 -53 0
-44 -62 0
-44 -71 0
-44 -80 0
-44 -89 0
-53 -62 0
-53 -71 0
-53 -80 0
-53 -89 0
-62 -71 0
-62 -80 0
-62 -89 0
-71 -80 0
-71 -89 0
-80 -89 0
-9 -18 0
-9 -27 0
-9 -36 0
-9 -45 0
-9 -54 0
-9 -63 0
-9 -72 0
-9 -81 0
-9 -90 0
-18 -27 0
-18 -36 0
-18 -45 0
-18 -54 0
-18 -63 0
-18 -72 0
-18 -81 0
-18 -90 0
-27 -36 0
-27 -45 0
-27 -54 0
-27 -63 0
-27 -72 0
-27 -81 0
-27 -90 0
-36 -45 0
-36 -54 0
-36 -63 0
-36 -72 0
-36 -81 0
-36 -90 0
-45 -54 0
-45 -63 0
-45 -72 0
-45 -81 0
-45 -90 0
-54 -63 0
-54 -72 0
-54 -81 0
-54 -90 0
-63 -72 0
-63 -81 0
-63 -90 0
-72 -81 0
-72 -90 0
-81 -90 0