#!/usr/bin/python

starting = int(input("Starting amount: "))
monthly = int(input("What is your monthly contribution? "))
interest = float(input("What is your yearly interest rate (computed monthly; 0.05 = 5%)? "))
interest_pm = interest/12
term = int(input("How long are you calculating for (in whole years)? "))

def compute_new_sum(principle, investment, pm_interest):
  return principle * (1+pm_interest)

def compute_new_sum_yr(principle, investment, interest):
  total = principle
  for month in range(12):
    total += investment
    total = compute_new_sum(total, investment, interest/12)
  return total

total = starting
print("Year,Total,Principle,PDV")
for year in range(term):
  total = compute_new_sum_yr(total, monthly, interest)
  princ = (year+1) * monthly * 12
  pdv = total - princ
  print(f"{year+1},{total},{princ},{pdv}")