Using the switch statement

Sorry here is this code again:
I just want to implement the idea: if the users inputs 20 it will turn pin13 high for a period of time and when the user inputs 200 it will turn pin 13 high for a longer period than the 20 case. 
As I mentioned in my previous post. My code is not complete. Yes I need to declare pin 13. But for now I just trying to get something from the input and later I'll use the input to do what I want.
I am just having problem.
I want to get and integer 20 when user inputs 20 and integer 200 when user inputs 200.
Thank


[#include <Keypad.h>

//new code start here
int k, amCount=0;
  //new code end here 

const byte ROWS = 4; // Four rows
const byte COLS = 3; // Three columns
// Define the Keymap
char keys[ROWS][COLS] = {
  {
    '1','2','3'    }
  ,
  {
    '4','5','6'    }
  ,
  {
    '7','8','9'    }
  ,
  {
    '*','0','#'    }
};
// Connect keypad ROW0, ROW1, ROW2 and ROW3 to these Arduino pins.
byte rowPins[ROWS] = { 
  9, 8, 7, 6 };
// Connect keypad COL0, COL1 and COL2 to these Arduino pins.
byte colPins[COLS] = { 
  12, 11, 10 }; 

// Create the Keypad
Keypad kpd = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

#define ledpin 13

void setup()
{
  digitalWrite(ledpin, HIGH);
  Serial.begin(9600);
}

void loop()
{
  char key = kpd.getKey();
  if(key)  // Check for a valid key.
  {
    switch (key)
    {
    case '100':
      digitalWrite(ledpin, LOW);
      break;
    case '3':
      digitalWrite(ledpin, HIGH);
      break;
    default:
      Serial.println(key);
    }
  }
}

]