a - b = 29 => a = b +29
a - c = 39 => a = c + 39
b + 29 = c + 39 => b mai mare decat c cu 10 => b = c+10
a = b + 29 = c + 10 + 29 (ecuatia 1)
a = c + 39 (ecuatia 2)
din ecuatia 1 si ecuatia 2 => b = 10
a - b = 29 => a = 29 + 10 = 39
a - c = 39 => 39 - c = 39 => c = 0
