I have a F1 student visa and cannot find this number. People keep saying the number written in red but there is no number written in red on my 1-20. all i have is my I-20 and I94. The only this in my passport is the I94 card. there aare no other numbers. Please help me find this!there is no stamp that has a number. just a number written underneath the stamp. It starts with an N and is 10 numbers long. is this it?