#include <stdio.h>

 int octal_sum(int a,int b) {
    int sum=0, carry=0, d=0, m = 1;
    while(a || b || carry) {
        d=0;
        d=carry+(a%10)+(b%10);
        a/=10;b/=10;
        if(d>7) {
            carry=1;
            d=d%8;
        } else {
        	carry = 0;
        }
        sum += d*m;
        m *= 10;
    }
   return sum;     //returns octal sum of a and b
}

int main(void) {
	printf("%d\n", octal_sum(20, 62));
	return 0;
}