A rural child specialist has to find the weight of five children of different ages. He knows from past experience that each of the children weighs less than 30 Kg, and all five weigh different amounts. Unfortunately, the scale available in the village can measure weight only over 30 Kg, so the doctor decides to weigh the children in pairs. His new assistant weighed the children without noting down the names. The ten weights recorded were: 35, 36, 37, 39, 40, 41, 42, 45, 46 and 47 Kg. The weight of the lightest child is: