Why is it only executed once the repeat is turned?

#define _CRT_SECURE_NO_WARNINGS 
#include <stdio.h>

int main(void) {
    int num1;
    int num2;
    printf("Enter integer 1 : ");
    int a = scanf("%d", &num1);
    printf("Enter integer 2 : ");
    int b = scanf("%d", &num2);

    while (1)
    {        
        if (num1 >= num2)
        {
            if (num1 % num2 == 0) ;
                printf("a");
                printf("Maximum number of pledges: %d",num2);
                break;
            }
            else {
                num1 = num2;
                num2 = num1 % num2;
            }
        }
        else if (num1 < num2)
        {
            if (num2 % num1 == 0) {
                printf("Maximum number of pledges: %d", num1);
                break;
            }
            else {
                num2 = num1;
                num1 = num2 % num1;
            }
        }
    }

    return 0;
}