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Competitions

Five for week 06

The thread

Mishascoreda carnationina plate, andMashapulla threadaround themand get aconvex polygon, whichisasmallerstud.

SinceMishaonce againwatch soccerandhe has no time, help themcalculate the area of​​apolygonof minimal area,therebychecking thequalityof workmeet the followingMasha.

Input

The first lineof eachtest casecontains anumber of goalsMischanailsN (4N105). In the nextN linesfor eachtest casethere are Npairs of numbersXi and Yi - the coordinatesof the nextnail.All coordinatesdoes not exceed themodulo109. It is guaranteedthat notwoare not the samenail.

Input dataendingline containing0.

Output

For eachtest casein a separateline outputthe desiredareawith thetwo charactersafterthe decimal point.

Time limit 1 second
Memory limit 64 MiB
Input example #1
4
1 0
0 0
0 1
1 1
0
Output example #1
0.50