Map millis to servo

Hi try to do a little timer for my son that have some time depending of the switch he press.
Here the code

#include <Servo.h> 
 
Servo myservo;  // create servo object to control a servo 
                // a maximum of eight servo objects can be created 
 
int pos = 0;    // variable to store the servo position 
int temps = 0;
const int buttonPin2 = 4;
const int buttonPin3 = 5;
int buttonState_2 = 0;
int buttonState_3 = 0;
int buton1time2 = 30000;
int buton1time3 = 60000;
long int millisstart;
long int millisend;
int second = 1000;
 
void setup() 
{ 
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
  pinMode(buttonPin2, INPUT);
  pinMode(buttonPin3, INPUT);
 Serial.begin(9600); 
 
} 
 
 
void loop(){ 
buttonState_2 = digitalRead(buttonPin2);
buttonState_3 = digitalRead(buttonPin3);
myservo.write(0);
if (buttonState_2 == LOW) {     
    temps = buton1time2; 
  } 
if (buttonState_3 == LOW) {     
    temps = buton1time3; 
  } 
if (temps != 0){ 
{ 
  millisstart = millis();
  millisend = (millisstart + temps);
    int val;
    while(millis() < millisend){
    val = millis();
    val = map(val,  millisstart, millisend, 0, 180);
    myservo.write(val); 
    Serial.println(val);    // tell servo to go to position in variable 'pos' 
    delay(250); 
    }    // waits 15ms for the servo to reach the position 
    temps = 0;
  }
  
  
}
}

Code work good with the 30 second but when i try 60 second it does not work, when i check the val on the serial, i receive some strnge value.
Thanks in advance

A sixteen bit "int" cannot represent 60000. Use unsigned long

      int val;
      while(millis() < millisend){
        val = millis();

All variables used for timing using millis() need to be unsigned longs