Write the codes and draw the flow chart for these problem. 

1.Please only use “if” flow control, write a program to ask the user to input his/her letter
grade (A,B,C,D,F), and
If input “A”, show “Excellent!”;
If input “B”, show “Well Done!”;
If input “C”, show “Keep Working Hard and You Should Do Better Next Time!”;
If input “D” and “F”, show “Please Don’t Give Up!”;
If input other letters, show “Invalid grade, please try later.”

2. Please use “if ... else” ladder flow control, write a program to ask the user to input
his/her letter grade (A,B,C,D,F), and
If input “A”, show “Excellent!”;
If input “B”, show “Well Done!”;
If input “C”, show “Keep Working Hard and You Should Do Better Next Time!”;
If input “D” and “F”, show “Please Don’t Give Up!”;
If input other letters, show “Invalid grade, please try later.”