Number of Stacks: 2
Push: Push the items in S1 and Push the item to S2 if the item (top) is less than S1
Pop: Pop the item from S2 because its min value and compare with S1, if both are same then pop item from S1 also.
Popped item is min
Push: Push the items in S1 and Push the item to S2 if the item (top) is less than S1
Pop: Pop the item from S2 because its min value and compare with S1, if both are same then pop item from S1 also.
Popped item is min
