A 75yrs old man got collapse and was rushed to the hospital. He was given oxygen to sustain him for 24hrs. After some time he was getting better, so the doctor gave him his bill of $1000. When he saw the bill he started crying, the doctor told him not to cry because of the bill that he could pay it in installments. But the man said: "I'm not crying because of the money i can pay you all in cash. I'm crying because, for just 24hrs of using your oxygen, I'm to pay $1000. But I have been breathing God's air free for 75yrs now, if I'm to pay, do you know how much I owe?