Types: Y1: int, M1: int, D1: int, Y2: int, M2: int, D2: int  
Ranges: 1 ≤ Y1 ≤ Y2 ≤ 10^18, 1 ≤ M1, M2 ≤ 12, 1 ≤ D1, D2 ≤ 31 (for months 1, 3, 5, 7, 8, 10, 12), 1 ≤ D1, D2 ≤ 30 (for months 4, 6, 9, 11), 1 ≤ D1, D2 ≤ 28 (for February in a non-leap year), 1 ≤ D1, D2 ≤ 29 (for February in a leap year)  
Addtl Info: Y1, M1, D1 is a date that is at least 0 days before Y2, M2, D2