Input:
     F 10
     F 20
     F 30

smarinel: ~/CSC/206-Project/Hw> java AvgIncome
Gender: F Amount: 10.0
Gender: F Amount: 20.0
Gender: F Amount: 30.0
For 3 females, the average income is 20.0
For 0 males, the average income is NaN

     M 10
     M 20
     M 30

smarinel: ~/CSC/206-Project/Hw> java AvgIncome
Gender: M Amount: 10.0
Gender: M Amount: 20.0
Gender: M Amount: 30.0
For 0 females, the average income is NaN
For 3 males, the average income is 20.0