num = int(input("Input a four digit numbers: "))  
x  = num //1000  
x1 = (num - x*1000)//100  
x2 = (num - x*1000 - x1*100)//10  
x3 = num - x*1000 - x1*100 - x2*10  
print("The sum of digits in the number is", x+x1+x2+x3)