GCD Using While Loop In Python 

The HCF or GCD of two integers is the largest integer that can exactly divide both numbers (without a remainder).

GCD: greatest common divisor 

Program:

n1=int(input("Enter n1 integer: "))

n2=int(input("Enter n2 integer: "))       

    

while(n1!=n2):

        if(n1 > n2):

            n1 -= n2;

        else:

            n2 -= n1;

print("GCD = ",n1);

OutPut:

Enter n1 integer: 81

Enter 21 integer: 153

GCD =  9