I am trying to use Zoho for Risk Assessment calculations 

I have written this code

if(Liklihood = "Low")

{

L_number = 1;

}

if(Liklihood = "Medium")

{

L_number = 2;

}

if(Liklihood = "High")

{

L_number = 3;

}

if(Impact = "Low")

{

I_number = 1;

}

if(Impact = "Medium")

{

I_number = 2;

}

if(Impact = "High")

{

I_number = 3;

}

Total = I_number + L_number;

if(Total <= 3)

{

input.Single_Line = "Accept";

}

if(Total >= 4)

{

input.Single_Line = "Manage";

}

I have a field on my form with a deluge ID of Singl_line, but when I run the form this field remains blank.  What am I doing wrong ?