Remember how creating a new 'DIS' inside the 'if' statement prevented it from working on the other variable with the same name? You are also creating a local version of 'DIS' in the scan() function. You are not making any change to the global variable named 'DIS'. Again, the fix is to remove the type 'int' in the line where you set the local 'DIS' variable. That will allow the scan() function to change the global 'DIS' variable so the movement() function can see the value.
It is good practice to use a capital letter at the beginning of global variable names and a lowercase letter at the beginning of local variable names.